Topic 31 "The turning Earth and the stars": your read (2 October 2026)

Two readers answered 118 items cold and agreed every key with each other and with the course. Their flags were all shape and wording, and all were applied in v2: in the whole "what is really moving?" family the key was the only option opening with a capital letter (Earth, or a child's name) while every distractor opened with "the", and two items added a colon or an "and"; the Sun distractors reused on a stars stem and a Moon stem left two options dead; three keys were the longest by a clause; the typed "orbit" was printed in an earlier stem; "spins very smoothly and slowly" gave the wrong reason for feeling nothing; "next January" was right only because December was not offered; and Paul, Pedro and Phoebe ran as three P-names.

Reader C then read the whole v2 bundle, 122 items, and agreed every key; every item had one true option a strong Grade 4 student could reach from the stem and the drawing. One item would not ship as it stood: the practice item that put the watcher on a ship at sea, where "the ship is sailing along" is literally true. Smaller notes: a bank key that was the only option with a comma clause (PP-23), one that was the only option with "and" (PP-44), what a typed "24 hours" should do when the stem asks for a name, and three key runs, which turned out to be the bundle's seeded shuffle and not the course's letters. All applied in v3; no key letter changed.

A sound topic that teaches the right things at the right depth, the reviewer said: Earth drawn from above the North Pole with the arrow the right way for that view, the lit half on the Sun's side, the whole-sky card moving the Sun, the Moon and the stars the same way, Orion in January and the big triangle in July honest for Dallas, and Topics 31 and 32 agreeing about the Moon. Four things had to change, and did. The spin strip and animation moved the red town dot round a disc whose land stood still, a town sliding over a fixed Earth, the opposite of "the sticker goes round with the globe"; the land now turns with the dot and only the shading stays toward the Sun. "Earth spins so smoothly and so slowly that nobody can feel it" gave the wrong reason: we feel nothing because the motion is steady, not slow; every line, feedback and key now says "smoothly and steadily". The "what is really moving?" family's options are now full short sentences, each stem with its own distractors (never "the Moon is travelling around Earth", which Topic 32 teaches as true). And Topic 30's own Sun-path sentence is recalled word for word. Worth fixing, all done: L04's rule was false of the Big Dipper and the W (both up all year), so it names Orion and the article adds the Dipper's exception; the bank's star-pattern block was L03's quiz with the nouns changed and is re-patterned; "next summer" and "next winter" against real distractors; "orbit" stripped from every stem before the typed item; cause before effect in four idea lines; Pedro renamed. The reviewer answered the author's seven questions as the page above shows.

What a student notices first is the spinning Earth: Sun left, lit half left, one arrow over the top, the red town dot going round the right way; the orbit a clean near-circle; the star pairs making their point without words. Then the faults, all fixed: the spin strip cut off at its fifth disc (frame widened); a figure with two red towns (one dot, inside the turning group); the kite pattern drawn over the barn and its stars leaving the panel, the sky swinging back the wrong way (re-placed, one-way motion); "JANUARY EVENING" chips hanging off their panels (placed from their own width); the birthday chip across the dashed orbit (moved clear); item letters and time chips under the 13 px floor at phone width (a 14 px chip on every item, the pick item in two rows); a letter chip sitting on a sunlight ray (the middle ray dropped on item forms); and, from the guidance review, the land turning with the dot. Every star-pair shift was measured (all move up and right; with no compass drawn this reads as rising, and the record names the simplification). The page pass found the 360 px column rendering wide, a site-engine fault since fixed in the shared builder.

52 items in content/G4T31_pp100_bank.py: 47 four-option MCQs and 5 typed (the number 24, the number 365, orbit, year, Earth). Per atom: SPA4-007 the spin 11 · SPA4-008 the trip 12 · SPA4-005 patterns keep shape 10 · SPA4-006 seasons 8 · SPA4-009 the capstone 11. Easy 14, medium 24, hard 14, sorted easy to hard and rising with the atom's place in the topic. MCQ keys A 11 · B 12 · C 13 · D 11. Eighteen question types, one exemplar each on the type sheet: how long one spin or one trip takes (one fixed set, the key tells them apart); what we call that time; how many spins or trips in a given time; where the town dot or Earth is after a given time on a lettered drawing; the correct reason (nobody feels the spin; a year is 365 days); what is really moving when the Sun, the stars or the Moon seem to; a child's claim is wrong, pick the reason; the term and its other word; a drawn sky pair (how many stars moved on their own; what the group did; place and shape); two photos compared; the seasons (gone in summer, back next summer); a turning floor at a museum; typed number or word; two ideas chained; the rule run backwards (Earth stops spinning). Every scene is fresh against the lessons, quizzes and practice (the scene-noun grep is in the build record), and the type sheet lists the draw constraints.

Skill: course-build → write-lesson (L01, L02 fact lessons on one thing each, coining "day" and "year" last; L03 a concept introduction in the fact form coining "star pattern"; L04 a fact lesson on a seasonal pattern; L05 the capstone recognition lesson) → design-check-sequence, sentence-atomise, write-example-sequence and write-explanation (the last two applied from write-lesson's dispatch text), write-mcqs (quizzes, attached questions, practice, the PP100 bank and its type sheet); write-video-script (intro, five lesson scripts, summary; the elementary micro-lesson anatomy); review-figures (author self-check on every render and every built page; the non-author pass is owed) @ efd8fba

Grade 4 Topic 31 — The turning Earth and the stars — build record (v1, 2 October 2026)

What this is, in plain words

Five short lessons that give a nine-year-old the two motions of Earth and what they do to the sky. Earth spins around once in a day (L01). Earth travels once around the Sun in a year (L02). A star pattern keeps its shape all night while the whole pattern moves (L03). Different star patterns are in the evening sky in different seasons (L04). And the capstone: the Sun, the Moon and the stars only SEEM to move, because Earth is the thing turning (L05). This is the topic that finally says "seems to move" out loud; Grade 3's sky topics and Topic 30 described the patterns and left the cause for here. Nothing here explains WHY it is night, which way Earth spins, or why the seasons happen — those are Grade 5's and grade 6-8's, and the register says so.

Hand-over from Topic 30 (not on disk when this was written; its folder does not exist yet). Topic 30's row is patterns only: the Sun's daily path (rises toward the east, highest around midday, sets toward the west), day length through the year, reading a season from data, predicting the next step — no cause. This topic takes that observed path as a fact to recall (L05's first quiz item and forest line use the REGISTER's words for SPA4-001, pending Topic 30's own sentence) and supplies the cause at recognition level: Earth spins. When Topic 30 lands, its exact Sun-path sentence should replace the register's wording in L05's forest line 1, script beat 2 and quiz q1 (one grep: "rise toward the east").

Decisions made without a blueprint (one line each, with the reason)

1. Lesson order 007 → 008 → 005 → 006 → 009, as the architecture row gives it — the spin and the trip first because the star lessons lean on "day" and "year", and the capstone last because it needs the spin (L01) and the moving patterns (L03).
2. "spins" is the one verb for Earth turning on itself; "turning" is the title's word and is said once in L01 ("The real Earth is turning like this right now") as the gloss — one word for one thing.
3. The Sun, the Moon and the stars "seem to move", never "move", in every line from L03 on; L05's rule says "It is Earth that is turning, not the sky" — the register's example (trees past a car window) is the L05 headache.
4. L01 shows the lit half and the dark half and never asks why it is night — the brief asked for the day side lit; the register puts the day-and-night explanation at Grade 5 (SPA5-005); the article says only "the half facing the Sun is lit up" / "the other half is dark".
5. Earth is drawn from above the North Pole, not from the side — the town dot then travels the whole rim and comes back, which is the fact taught; the spin arrow is one curved arrow over the top, counterclockwise (true for that view); no direction is named in text.
6. "day" and "year" are coined terms (recognition and typed recall items, S34) — they are everyday words, but the atoms give them their science meaning ("one spin is one day"); James may strike them from terms (question 4).
7. "orbit" is recalled, not coined — Grade 3 Topic 31's sentence word for word ("Earth travels around the Sun along a path called an orbit"), one recall item first in L02's quiz; "one trip around the Sun" is the plain phrase and the word arrives after it.
8. No tilt is drawn, no cause of the seasons, no "axis", no leap year — grade 6-8's and Grade 5's; "about 365 days" and "about 24 hours" carry the simplification.
9. "star pattern" is the student's word; "constellation" is named once in L03 as the word people who study the stars use, and tested by one recognition item in L03's quiz and one in the bank; both are RECALL_BY_MCQ (eleven and thirteen letters).
10. L03 is examples only (no non-example) — the Forces log's rule for a universal attribute: the Big Dipper at two times, the W at two times, then the whole sky moving together; the one "wrong" sky (a star displaced) appears only as a drawn candidate in the pick item, where it IS the belief being tested.
11. L04 adds one honest fact beyond "patterns only": "In July, Orion is in the sky in the daytime, so the Sun's light hides it" — it answers the child's "where did it go?" and kills "the stars disappear"; it is one line of fact, no orbit geometry (question 2).
12. L05 is recognition, not explanation — the register's chain (G4 recognises, SPA5-005 explains) is not compressed: nothing about which way Earth spins or why east-to-west.
13. The star-pattern drawings move a pattern without tilting it — a named simplification (the real Dipper also turns a little over three hours); the captions say "moved", never "slid across level" (question 5).
14. US sky names: the Big Dipper (not the Plough), Orion in winter, "a big triangle of three bright stars" in summer (the Summer Triangle, unnamed); the W is Cassiopeia, unnamed.
15. Figures by kind: code draws the spinning Earth, the orbit (Grade 3 Topic 31's drawer, imported), the sky panels, the whole-sky card, the tables and rule cards; a night sky, the Big Dipper and a sunrise are photo placeholders; the five class scenes are cartoon placeholders. No person or hand as a glyph.
16. Every lesson gets a video — each atom is one picture that moves (a spin, a trip, a sliding pattern, a season swap, the whole sky), and the register's "seem to move" is best shown moving.

Questions for James (one line each; the build does not wait)

1. L01 draws the lit half and the dark half and never asks why it is night — keep it at that line? Recommendation: yes; the Grade 5 lesson explains it, and the drawing shows what the brief asked for without claiming more. Built that way.
2. L04's one line "In July, Orion is in the sky in the daytime, so the Sun's light hides it" goes one fact beyond "patterns only" — keep or cut? Recommendation: keep; it is the honest answer to "where did it go?" and it uses Grade 3's "still there" sentence. Built in, with a quiz reason item and a bank reason item on it.
3. "constellation" is named once in L03 and tested by one recognition item in the quiz and one in the bank — keep the items? Recommendation: keep (recognition only, never typed).
4. "day" and "year" sit in terms as coined words (each with a recognition MCQ and a typed recall) — keep them as terms, or treat them as everyday words with no term items? Recommendation: keep; the typed "day" and "year" are the bank's cheap hard items.
5. The drawn patterns move as a whole without tilting (the real Dipper turns a little in three hours) — accept the simplification? Recommendation: accept; clarity beats accuracy here, and the caption claims only "moved".
6. "axis" is not coined ("spins all the way around" is the phrase) — leave it to Grade 5? Recommendation: yes.
7. L04's quiz has 7 items (S18 WARN) — fine for a one-fact lesson? Recommendation: yes; the honest items are used up, and padding would add obvious ones.

Counts

• Lessons 5; article words L01 249 · L02 265 · L03 286 · L04 272 · L05 291 (all under 300, a subtitle or figure every ≤ 8 lines); scripts L01 138 · L02 142 · L03 147 · L04 142 · L05 149 spoken words (≤ 150); intro 113 words, 3 question marks (at the limit, one is the ready line); summary 131 words, opener exact.
• Quiz items L01 8 · L02 10 · L03 9 · L04 7 · L05 9 = 43; attached questions 5 + 3; practice 15 (3 Grade 3 retrievals, 1 FRQ, 2 typed terms); figures 41 (33 SVG by code, 3 photo placeholders, 5 cartoon placeholders).
• PP100 bank 52: per atom SPA4-007 11 · SPA4-008 12 · SPA4-005 10 · SPA4-006 8 · SPA4-009 11; tiers easy 14 · medium 24 · hard 14; typed 5 (24 hours, 365 days, orbit, year, Earth); 47 four-option MCQs; 0 multi-select; types 18 (records/TYPES_G4T31.md).
• Blind bundle blind/2026-10-02: 107 mcq, 10 text, 1 frq (118 held), 11 [Drawing: lines.

The per-lesson table

design-check-sequence records

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Skill: design-check-sequence @ efd8fba

Part: L01 — Type (a): one fact applied once (how long one spin takes; what one spin is called). Plan: 8 items, 2-4 options, stems ≤ 20 words; order recognise → apply → produce; term item last; no reference table. Belongs in practice/test: the 4-option HOW LONG set, the counts over weeks.

Part: L02 — Type (a): one fact applied once. Plan: 10 items (one Grade 3 recall first), the drawn orbit item as the apply; the three claims; the two typed terms last after their recognition MCQs. Belongs elsewhere: the two-step "365 spins → one trip" (bank, hard).

Part: L03 — Type (a) on a categorical fact (does the shape stay? yes); the drawn pair and the drawn pick are the fluency run; the term items after every stem that prints "star pattern". Belongs elsewhere: the 2 × 2 place-shape form and the "what can he copy" two-step (bank).

Part: L04 — Type (a): one seasonal fact. Plan: 7 items; Grade 3 recall first; one reason item (the correct reason Orion is gone); two claims. Belongs elsewhere: the notebook two-step (bank).

Part: L05 — Type (c): what (q2, q3), why (q7, a fresh case: every pattern together), misconception (q4 bare yes / no; q6 TRUE), transfer (q5 the fair ride; q9 the imagined removal), plus Topic 30's recall first. Belongs elsewhere: "X is wrong — the correct reason" four-reason forms (bank).

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Key strings (written out and checked)

• Attached questions in video order (L01 … L05, S1, S2, S3): B B A B A A B A — A 4 of 8, no position over 60 %.
• L01: 3-option 0 1 0 2 · 2-option 0 1 · 4-option 0. L02: 3-option 0 2 2 0 · 4-option 2 · 2-option 1 0 1. L03: 2-option 1 0 0 1 0 · 3-option 0 1 1 0. L04: 3-option 0 1 1 2 · 2-option 1 1 0. L05: 3-option 1 0 1 · 2-option 0 1 1 0 1 0 (no four in a row alternate).
• PP100 MCQ keys: A 11 · B 12 · C 13 · D 11; string BCBBDACDDCABDCBABBDCDABDCAADBCADACBDCACBACCADBC. Key-is-the-longest-option check by script: 0 hits (twelve were found on the first pass and fixed by lengthening a distractor or shortening the key).
• Lettered items (one list, figures.LETTERS): q_spin_jklm dot at J, key J (back after 24 h); q_orbit_jklm Earth at J, key L (opposite, 6 months); pp_spin_npqr dot at Q, key Q; pp_spin_stvw dot at W, key T (opposite, 12 h); pp_orbit_npqr Earth at P, key P; pp_orbit_stvw Earth at T, key W (opposite); q_pick_jk true candidate J. Convention: spin letters run top → left → bottom → right (the arrow's direction, counterclockwise from above the pole); orbit letters run in the arrow's order from the upper right. No order items.

The rules applied (the brief's table)

Misconceptions confronted (the vault catalogue is silent on astronomy; sources named)

Checker results

• python3 build_tools_check_topic.py grade4/topic31_build/content/G4T31.py → 0 FAIL, 19 WARN, every WARN answered:
• S8 (12): script beats of three sentences — kept, each beat is one screen state (the shape every accepted Grade 4 topic has).
• S18 (1): L04's quiz has 7 items — kept (question 7): a one-fact lesson; its honest items are used up.
• S36 (6 words): pm (the time notation, "9 PM" — fine, needed for the two-times drawings); spun (the past form of spin, the topic's verb — fine); recognize (in the coining sentence "a shape you can recognize" — fine, the plain meaning is the only one); globe (L01's object, a classroom word — fine); museum (two bank scenes — fine, an everyday word); scientist (two bank scenes — fine). Swapped before this record: "scooping" → "with a long handle"; "horizon" → "the land".
• S17, S23, S28, S1, S25 all cleared during the build (first run: 14 FAIL — four long lines, six three-sentence bank stems, four scripts over 150; all fixed).
• python3 grade4/check_g4_articles.py … → 0 FAIL (counts above).
• python3 build_tools_names.py Santos Paul Pedro Phoebe → all free, exit 0.
• python3 build_tools_build_topic_site.py … /tmp/g4t31.html → 5 lessons, 15 practice, 52 pp100, 41 figures; every article route and L03's quiz route screenshotted and read.
• check_svg_ids.py grade4/topic31_build/content/figures.py → PASS (0 ids written here; two NOTE lines on Topic 29's counter-numbered gradients, identical definitions).
• build_tools_blind_bundle.py … blind/2026-10-02 → 107 mcq, 10 text, 1 frq, 118 held. The bundle's 11 [Drawing: lines grepped for spins|turns|orbit|same shape|moved|season: 3 hits, all the phrase "orbit diagram" naming the drawing on the three lettered orbit items, whose keys are letters — the word is the figure's name, not an answer; 0 hits for spins, turns, same shape, moved, season. The star-pattern items' blind text gives each star's position as numbers in both panels, never "the same shape".
• build_tools_video_batch.py → 7 videos (intro, L01–L05, summary), handoff/G4T31/videos/batch_G4T31.json + READY.md; check_brief.py → 6 ✓ and the INTRO's standing R79 closing-bullets line (an intro has no rule slide; accepted on every topic) plus a "3 question marks — at the limit" note; grep -ci strand → 0. NOT SENT — Grade 4's first batch waits for James's word.

Figures (41; author's review-figures self-check on every render, then every built page)

Depiction register in figures.py's docstring. Rendered to /tmp/g4t31_figs/ and read on two contact sheets and the six page screenshots. Fixed on the render: Orion's join lines made the letter Z (consecutive points) — an edge list now draws the hourglass; the Summer Triangle closed; the night band's arrows were ink on navy (invisible) — now pale; item-panel stars enlarged above the background dots; the PEDRO'S BIRTHDAY chip overlapped the Earth label — moved below; the two "shape changed" item panels (a sky that can never happen) dropped, the one wrong candidate kept only in the pick item where it is the belief under test. Guards: Topic 18's table asserts every cell fits its column (two tables pass). Simplification named: a pattern at a second time is a translation of the first (no tilt).

Sentence-atomise self-check (summary per lesson; one idea per sentence, S1 / S38 clean)

Judgement calls

1. The day-and-night drawing (lit half, dark half) with no why. Chosen over a side view so the tracked town comes back to its start; the words stay with what the picture shows. James's question 1.
2. Orion "up in the daytime" in L04. One fact beyond the atom, kept because it is the natural answer and uses Grade 3's sentence; the cause (Earth's place on its orbit) is not given. Question 2.
3. A pure translation for the moved pattern. The sky really turns about the pole star; a nine-year-old reading "same shape, moved together" is the atom; a rotation would read as a changed shape. Question 5.
4. The bank's HOW LONG set shared by the spin and the trip. The set is the discrimination the day/year confusion needs; the key tells them apart.
5. The capstone's MOVING set carries "the clouds, pushing the Sun along" as the fourth option — a documented young belief (Baxter's cloud models), not padding.
6. The Moon in L05. The Moon really does travel around Earth (Grade 3's fact), but its nightly crossing is Earth's spin; the lines say the Moon "seems to move across the sky the same way", never "the Moon does not move".
7. The intro's three question marks — the two felt questions and the ready line; at the limit, not over.

Owed

• The non-author review-figures pass over the 33 SVG renders and the 8 placeholders' briefs; the non-author review-questions pass over 43 quiz, 8 attached, 15 practice and 52 bank items; the blind read of blind/2026-10-02 (two cold readers) and its adjudication.
• The picture pass through David's pack (8 placeholders) — this topic carries Questions for James, so it waits for his sign-off.
• The video batch (7) — built and checked, not sent; James's word is needed for Grade 4's first batch.
• When Topic 30 lands: replace the register's Sun-path wording in L05 (forest line 1, script beat 2, quiz q1) with Topic 30's own sentence.
• Nothing committed (the brief's instruction).

v2 — reviews applied (2 October 2026)

Skill: course-build → write-lesson (lesson lines, scripts via write-video-script), write-mcqs (every item change; check_key_tells.py 0), write-explanation (fb and why lines), review-figures (author re-render of every changed drawer and every built page) @ fb37d14

In plain words. Three reviews (the guidance review, the figure review and the blind read) found one figure that contradicted the lesson, one wrong reason sitting in a key, a family of items whose key stood out by its shape, and a boy's name too close to his classmate's. All are fixed in place: the land on the spinning Earth now turns with the town, the spin is "smooth and steady" (not "slow"), every "what is really moving?" option is a short full sentence, Pedro is now Andre, Topic 30's own Sun-path sentence is recalled word for word, and the seasons rule names Orion rather than claiming every winter pattern leaves. Every key keeps its letter and meaning; the attached-question string, the quiz strings and the bank's key string are unchanged from v1.

Finding → change

Judged differently or beyond the rows. (a) The Dipper line went into the SCRIPT as well as the article (the two are alternatives), paid for by trimming beat 1 ("Dallas backyard"; "Above the fence shine seven bright stars, three in a short straight row") and beat 3 ("It is still there."). (b) "near the North Star" names a star the course has not coined; it is the plainest true reason and the reviewer's wording. Caveat for the record: from Dallas the Dipper sits very low in the north on fall evenings; "you can find it on evenings all year" is the grade-4 truth, exact from Kansas. (c) The seasonal items about unnamed made-up patterns (L04 vq, q2; PR-8; PP-27) keep their keys: the article now says "most star patterns have their own season", and each stem is a pattern seen in one season, which is the case the rule describes. (d) L05's "It is as if the whole sky were one big picture." was cut to bring the article under 300 words after the two-line Topic 30 sentence went in. (e) The bank's drawn pairs took NEW patterns (M, arrow, cross) rather than the lesson's Dipper, W and kite with new chips — the review asked for an arrow, a cross and an M. (f) A pattern constant named ARROW silently overwrote the arrow colour and every spin arrow's arc vanished on the render — caught on the PNG, renamed ARROW_STARS; a reminder that the render, not the source, is the check.

Record corrections. v1's rule table claimed "S28 found 16 bank items that were quiz items reworded — every one re-scened": the review re-performed it and found the SPA4-005 block (PP-12, 13, 22–26, 30, 44) still L03's items with the nouns changed; v2 re-patterns and re-cases them (W7 above). v1's figure row "all five article routes … screenshotted and read" had not caught the still land, the two dots or the clipped strip; v2's page pass is listed below. v1's hand-over note ("Topic 30 … its folder does not exist yet") is closed: Topic 30 is on disk and its sentence is now recalled.

Checker lines (final run)

• python3 build_tools_check_topic.py grade4/topic31_build/content/G4T31.py → 0 FAIL, 19 WARN — S8 ×12 (three-sentence beats, each one screen state — kept), S18 ×1 (L04's 7 items — kept, question 7), S36 ×6 (pm, spun, recognize, globe, scientist, museum — all answered in v1; no new word flagged: steadily, Andre, Vermont, cross, aunt, photo all passed).
• python3 grade4/check_g4_articles.py … → 0 FAIL; articles L01 248 · L02 259 · L03 285 · L04 293 · L05 293; scripts 142 · 142 · 147 · 150 · 149; intro 113; summary 132.
• python3 build_tools_names.py Santos Paul Andre Phoebe → all free, exit 0; grep for "Pedro" over content/, NAMES_POOL.md, build_tools_video_batch.py, handoff/G4T31/ → 0.
• check_svg_ids.py grade4/topic31_build/content/figures.py → 41 figures, 20 ids, 0 shared, PASS.
• check_key_tells.py grade4/topic31_build/content/G4T31.py → KEY TELLS: 0 of 107 MCQs flagged (a: 0, b: 0, c: 0) (28 fixed-set options exempt by name).
• build_tools_video_batch.py → 7 videos, handoff/G4T31/videos/batch_G4T31.json; check_brief.py → L01–L05 and SUMMARY ✓, the INTRO's standing R79 closing-bullets line and the "3 question marks — at the limit" note (both accepted on every topic); grep -ci strand 0. NOT SENT.
• build_tools_blind_bundle.py … grade4/topic31_build/blind/2026-10-02-v2 → 107 mcq, 10 text, 1 frq, 118 held; the 11 [Drawing: lines grepped for spins|turns|orbit|same shape|moved|season → 3 hits, all "orbit diagram" naming the figure on the three lettered orbit items.

Key strings (re-read on the built content; unchanged from v1)

Attached questions in video order B B A B A A B A. L01 0001021t · L02 02220101tt · L03 100011010 · L04 0111210 · L05 100110110 (t = typed). PP100 MCQ keys A 11 · B 12 · C 13 · D 11, string BCBBDACDDCABDCBABBDCDABDCAADBCADACBDCACBACCADBC; tiers easy 14 · medium 24 · hard 14; typed 5.

Changed ids

Lessons: L01 (forest 1, ideas 10 / 12 / 20, script beat 3, q2, q7, q8 accepts) · L02 (idea 16, q3, q9 accepts) · L03 (ideas 13–14 split, closing return, q8 source) · L04 (forest 4, ideas 19–20, rule, closing bullets, script beats 1 / 2 / 3 / 4 / 5, vq fb, q1, q2 fb, q4 why, q7 fb) · L05 (forest 1, ideas 6–7, 11, 13, closing return, script beat 2, vq, q1, q2, q3, q5, q7, q8). TOPIC: lexicon 4, summary beat 5, SUM-3. PRACTICE: PR-8 fb, PR-9, PR-10, PR-14 / PR-15 accepts. Bank: PP-10, 12, 13, 16, 18, 19, 22, 23, 24, 25, 26, 28, 30, 32 why, 33–38, 40 option, 43 / 48 accepts, 44, 47. Figures: spin_disc (and so earth_spin_headache, earth_spin, whole_sky_card), spin_strip, spin_anim, spin_letters (q_spin_jklm, pp_spin_npqr, pp_spin_stvw), orbit_headache, orbit_letters (q_orbit_jklm, pp_orbit_npqr, pp_orbit_stvw), sky_panel (orion_january, seasons_sky, every item panel), whole_sky_anim, pattern_two_times (q_kite_two), pattern_pick (q_pick_jk), rule_seasons; new keys pp_m_two, pp_cross_two, pp_arrow_two replace pp_w_two, pp_dipper_two, pp_kite_two; new chip14; four briefs. Names: every "Pedro" / "PEDRO" string.

Renders opened (review-figures, author re-check on the render)

/tmp/g4t31_v2_figs/png/: earth_spin, earth_spin_headache, spin_strip, spin_anim at 0 / 3 / 6 s, q_spin_jklm, pp_spin_npqr, pp_spin_stvw, orbit_headache, q_orbit_jklm, pp_orbit_npqr, pp_orbit_stvw, whole_sky_anim at 0 / 3 s, q_kite_two, pp_m_two, pp_cross_two, pp_arrow_two, q_pick_jk, orion_january, seasons_sky, whole_sky_card, rule_seasons — land turned with the dot on every spin render; one dot; arrow arc present; chips inside their panels; every star inside the night panel. Site built to /tmp/g4t31_v2.html; /tmp/g4t31_v2_pages/: the five article routes, the L01 and L03 quiz routes and the PP100 at 1200 px and in a true 360 px viewport (Playwright), full page, read in slices — every figure whole, the two-row pick item and the lettered discs read in the phone column.

Owed after v2

A second blind read of blind/2026-10-02-v2 (the family's options changed shape; PP-22 / 23 / 25 / 30 are new items); James's seven questions stand (the review's answers are recorded in REVIEW_G4T31_2026-10-02.md); the picture pass (8 placeholders) still waits for his sign-off; the batch is built and checked, not sent. Nothing committed.

v3 — polish (2 October 2026)

Skill: course-build → write-mcqs (every item change; check_key_tells.py at 0) → write-explanation (every changed fb and wrong_fb line) @ e23b67f

In plain words. A third cold reader (Reader C) read the whole v2 bundle, 122 items, and agreed every key. One item would not ship as it stood: the practice item that put the watcher on a ship at sea, where "the ship is sailing along" is literally true. The rest was small: two bank keys a child could pick by their shape (the only comma clause; the only "and"), a question about what a typed "24 hours" should do when the stem asks for a NAME, and three key runs the reader saw in the bundle. All applied below; no key letter, key meaning, tag, figure or script line changed, so the video batch stands as built and was not rebuilt.

Flag → change

Checks after v3

• python3 build_tools_check_topic.py grade4/topic31_build/content/G4T31.py → 0 FAIL, 20 WARN — v2's 19 (S8 ×12 three-sentence beats, S18 L04's 7 items, S36 pm / spun / recognize / globe / scientist / museum) plus S36 'anchor' ×2 (PR-10's stem and fb): kept — the stem explains it in the same clause ("held still by its anchor").
• python3 grade4/check_g4_articles.py grade4/topic31_build/content/G4T31.py → 0 FAIL; articles 248 / 259 / 285 / 293 / 293; scripts 142 / 142 / 147 / 150 / 149; intro 113; summary 132, opener ok.
• python3 ~/Documents/CourseBuilding-Vault/skills/write-mcqs/check_key_tells.py grade4/topic31_build/content/G4T31.py → KEY TELLS: 0 of 107 MCQs flagged (a: 0, b: 0, c: 0); KEY LONGEST (any margin) 18 of 107; 28 fixed-set options exempt.
• python3 ~/Documents/CourseBuilding-Vault/skills/review-figures/check_svg_ids.py grade4/topic31_build/content/figures.py → 41 figures, 20 ids, 0 shared, PASS.
• python3 build_tools_names.py Santos Paul Andre Phoebe → all free, exit 0.
• python3 build_tools_build_topic_site.py grade4/topic31_build/content/G4T31.py /tmp/g4t31_p.html → 5 lessons, 15 practice, 52 pp100, 41 figures.
• Video batch not rebuilt (no script line changed; handoff/G4T31/videos/batch_G4T31.json stands from v2) and not sent.
• Blind bundle re-cut: grade4/topic31_build/blind/2026-10-02-v3/ → 107 mcq, 10 text, 1 frq, 118 held, 10 adversarial rows; the [Drawing: lines grepped for spins|turns|orbit|same shape|moved|season → 3 hits, all "orbit diagram" (the figure's name on the three lettered orbit items); ship|sailing → 0.

Counts and key strings after v3

Unchanged from v2: 5 lessons · 43 quiz items (8 + 10 + 9 + 7 + 9) · 5 attached + 3 summary questions · 15 practice · bank 52 (47 four-option MCQs, 5 typed): SPA4-007 11 · 008 12 · 005 10 · 006 8 · 009 11; easy 14 / medium 24 / hard 14; bank MCQ keys A 11 · B 12 · C 13 · D 11, string BCBBDACDDCABDCBABBDCDABDCAADBCADACBDCACBACCADBC; the quiz, practice and attached strings as printed above (no option moved position).

Item ids changed in v3 (for the mini re-read)

Practice: PR-10 (stem, option B, fb B) · PR-14 (accept list, wrong_fb) · PR-15 (accept list, wrong_fb). Lesson quizzes: L01-08 (accept list, wrong_fb) · L02-09 (accept list, wrong_fb). Bank: PP-23 (option, why) · PP-44 (option, why) · PP-43 (wrong_fb). Code, not items: the bank's YEAR list and new YEAR_WRONG; typed() takes wrong_fb; the bank's header comment (the ship → the anchored boat). Records: TYPES_G4T31.md (bar list, v3 note); this section.

Judgement calls, v3

1. A name is not a duration. "Type the name for that amount of time" has one kind of right answer, the word; "24 hours" and "365 days" are the lengths of the time, so they are now a feedback line that says exactly that, and the student types again. This reverses part of v2's widening ("12 months", "twelve months", "365 days" on the year items) on the same ground; "a whole day", "a day and a night", "a whole year" stay, since they name the time.
2. The anchored boat, not the lighthouse. The reader offered either; the lighthouse keeper is already the summary's third question, and one scene per item is the course's rule.
3. The key runs were left alone. Re-ordering live options to fix a run that exists only in a seeded shuffle would move keys for no reason; the live strings are printed above and are clean.

Owed after v3

• A mini re-read of the changed items above (blind/2026-10-02-v3/) by a reader who has not seen the keys.
• James's questions on the Needs-you page (records/REVIEW_NEXT_G4T31.md → course_preview/review/REVIEW_NEXT_G4T31.html); the picture pass (3 photo and 5 cartoon placeholders) waits on them.
• James's notes on the scripts are the cue to send the seven-video batch.

Nothing committed.

Skill: course-build → write-mcqs → write-explanation, design-check-sequence @ efd8fba

Topic 31 — The turning Earth and the stars — the PP100's question types, with their exemplars (v1, 2 October 2026)

In one line: 52 items, 47 four-option MCQs and 5 typed (24, 365, orbit, year, Earth); eighteen types, because the five atoms each need a fact form, an apply form and a claim form, and the capstone needs the "what is really moving" form and the rule run backwards. MCQ keys A 11 · B 12 · C 13 · D 11. Difficulty rises with the atom's order: SPA4-007 (the spin) seven easy, three medium, one hard typed number; SPA4-008 (the trip) four easy, four medium, four hard (one chained, three typed); SPA4-005 (patterns keep shape) three easy, five medium, two hard; SPA4-006 (seasons) six medium, two hard; SPA4-009 (the capstone) six medium, five hard.

What this page is. James reads a bank as its question TYPES first (vault: A bank is reviewed as its question types first, one exemplar each). Under the Grade 4 standing brief the bank is built straight away (content/G4T31_pp100_bank.py); this sheet is the way in. Each type line says what the stem asks, what the four options (or the accept list) are, and prints one exemplar in full with its nearest lesson-side instance, so freshness can be checked in one look.

Rulings already applied. Four options on every MCQ (three fixed sets: HOW LONG "about 1 hour / about 24 hours / about 7 days / about 365 days", used for the spin AND the trip so the key tells them apart; WHAT WE CALL "an hour / a day / a week / a year"; WHAT IS REALLY MOVING, every option a short full sentence — the Sun stem "Earth is spinning around. / The Sun is traveling around Earth. / The whole sky is turning around Earth. / The clouds are pushing the Sun along."; the stars stem swaps in "The stars are flying across space." and "The wind is blowing the stars along."; the Moon stem "The Moon is sliding across the sky on its own." and "The wind is blowing the Moon along." — never "the Moon is traveling around Earth", which Topic 32 teaches as true; rotated per item); no option bundles a verdict with its reason (every claim is "X is wrong … What is the correct reason?" with four single-statement reasons; the one TRUE claim is "Paul is right that … What is the correct reason?"); every stem is a positive question of at most two sentences unless tagged hard (S23 clean); the lettered items read their letters from figures.LETTERS (one list for stem and drawing) and their blind text is data (which letter the dot or Earth sits at; the stars' positions as numbers), never the answer; the key is never the longest option by the key-tell checker's margins (check_key_tells.py: 0 of 107 flagged, v2); "star pattern" and "constellation" are recalled by MCQ (RECALL_BY_MCQ, eleven and thirteen letters); the typed keys are the numbers 24 and 365, and the words orbit (Grade 3's term), year and Earth (a name), with child spellings in the accept lists; no multi-select; every item names ONE atom; US spelling; units as words in prose, numerals on drawings.

The bar list (real things a generated item must never use): "axis", "rotate", "revolve", "hemisphere", "equator", "tilt", "leap year" (not taught); any cause of the seasons or of day and night (grade 5 / grade 6-8); the Sun or the stars "moving" (they "seem to move"); the Moon's monthly changes (Topic 32's); any lesson scene (the classroom globe and its sticker, Andre's birthday cake, Phoebe's grandmother's farm porch and barn in Kansas, Paul's Dallas backyard with his dad and the fence, Andre's car on the highway to San Antonio, the intro's bedroom window); any quiz, attached or practice scene (the spelling test, Andre's uncle, Phoebe's cousin, the fair ride, the anchored boat, the lighthouse, the tree ring, the school clock, the crown and fish patterns, letters J K L M); a claim-maker from another topic's row (only Paul, Andre and Phoebe); "biggest / smallest" for a time or a count (longest, most); a non-US sky name (the Plough).

The eighteen types

Hard because — type 9 (hard items): the belief is held against the rule and every distractor half-accepts it, so the key is not the odd one out. Type 16: the number or word is produced, not picked, from a fresh scene with no clue word in the stem. Type 17: two ideas chained (spins → days → one trip; shape stays and place changes; the season cycle and the year; the observed move and its cause). Type 18: the cause removed, the effect predicted.

One exemplar per type, in full

Type 1 (easy, SPA4-007). A scientist in Alaska times one whole spin of Earth. About how long is it? — about 1 hour / about 24 hours / about 7 days / about 365 days. Why: Earth spins all the way around once in about 24 hours. So one spin takes about 24 hours. (nearest lesson-side instance: L01-q1, the bare question with three options — here a timer and the four-option set)

Type 2 (easy, SPA4-007). From sunrise in Oregon until the next sunrise, Earth spins all the way around once. What do we call that amount of time? — an hour / a day / a week / a year. (nearest: L01-q5, the bare term question — here the scene is a place and a sunrise)

Type 3 (easy, SPA4-008). A scientist in Hawaii times one whole trip of Earth around the Sun. About how long is it? — about 1 hour / about 24 hours / about 7 days / about 365 days. (nearest: L02-q2, three options)

Type 4 (easy, SPA4-007). Andre's cousin spends one week at a camp in Colorado. How many times does Earth spin all the way around in one week? — 7 times / once / 24 times / 30 times. (nearest: L01-q6, the Friday spelling tests)

Type 5 (medium, SPA4-007, drawn). The red dot on this drawing of Earth is a town, at W. Where will the dot be after 12 hours? — S / T / V / W. Figure pp_spin_stvw; blind text: the letters' places and the dot at W. Medium because the half turn must be read as the opposite side. (nearest: L01-q3, the dot at J after 24 hours)

Type 6 (medium, SPA4-008, drawn). Earth is at T on its orbit today. Where will Earth be 6 months from today? — S / T / V / W. Figure pp_orbit_stvw. (nearest: L02-q3, Earth at J after 6 months)

Type 7 (medium, SPA4-007). Nobody on Earth can feel Earth spinning. What is the correct reason? — Earth spins very smoothly and steadily. / Earth is not really spinning. / Only the land spins, and the people stay still. / The air holds everyone still. (nearest: L01-q7, Andre's claim as yes / no)

Type 8 (medium, SPA4-009). From a beach in Florida, the Sun seems to move across the sky from morning to evening. What is really moving? — Earth is spinning around. / The Sun is traveling around Earth. / The whole sky is turning around Earth. / The clouds are pushing the Sun along. (nearest: L05-q2, three options, no place)

Type 9 (hard, SPA4-009). Paul says the Sun travels around Earth once a day, and that is why it seems to cross the sky. Paul is wrong. What is the correct reason? — Earth spins once a day, so the Sun only seems to move. / The Sun travels around Earth once a year, not once a day. / The Sun stays still and the sky turns around Earth. / The Sun crosses the sky because the wind pushes it. Hard because: the catalogued belief (Baxter 1989; Vosniadou and Brewer 1994) is held against the rule, and every distractor half-accepts it. (nearest: L05-q4, the same claim as bare yes / no)

Type 10 (easy, SPA4-005). Five bright stars make the shape of a cross in the night sky over Montana. What is a group of stars like this called? — a group of planets / a star pattern / a telescope / a cloud. (nearest: L03-q5)

Type 11 (medium, SPA4-005, drawn). Here are five stars at 7 PM and at 10 PM. How many of the five stars have moved on their own, away from the others? — none of them / one of them / two of them / all five of them. Figure pp_m_two (an M pattern); blind text: each star's position as numbers in both panels. (nearest: L03-q2, the kite as yes / no — a different move: a count of movers on a different pattern)

Type 12 (medium, SPA4-005). At 9 PM a star pattern is just above a mountain in Colorado. Which is true at midnight? — The pattern is in a new place, in the same shape. / … in the same place, in a new shape. / … in a new place, in a new shape. / … in the same place, in the same shape. (nearest: L03-q9, two options)

Type 13 (medium, SPA4-006). A big triangle of three bright stars is in the evening sky every July. After it goes, when will the triangle next be in the evening sky? — next week / next month / never / next summer. (nearest: L04-q4, three options)

Type 14 (medium, SPA4-006). The big triangle is in the evening sky in July but not in January. What is the correct reason? — In January its stars stop shining. / In January it moves far away from Earth. / In January it is up by day, hidden by sunlight. / In January the clouds hide it from us every night. (nearest: L04-q5, Orion in July — here the summer pattern in winter)

Type 15 (medium, SPA4-009). Paul stands on a slowly turning floor at a museum in Ohio, and the walls of the room seem to go past him. What is really moving? — The walls are moving around him. / The ground under the museum is turning. / Paul is turning with the floor. / The air in the room is moving him. (nearest: L05-q5, Phoebe on a fair ride)

Type 16 (hard, SPA4-009, typed). The Sun, the Moon and the stars all seem to move across the sky. Type the name of the thing that is really turning. — accept: Earth, the Earth, earth, planet Earth, our planet, erth … Hard because: the name is produced, not picked. (nearest: L05-q2, the MCQ form)

Type 17 (hard, SPA4-005). Andre draws a star pattern at 8 PM. At 11 PM he wants to draw it again without looking up. What can he copy from his first drawing? — the shape of the pattern / the place of the pattern in the sky / both the shape and the place / neither the shape nor the place. Hard because: two steps — the shape stays, the place changes, then the right one is chosen. (nearest: L03-q7, what Paul sees over two hours)

Type 18 (hard, SPA4-009). Imagine Earth stopped spinning. What would the star patterns seem to do at night? — still move across the sky / stay in one place in the sky / move across the sky the other way / change their shapes. Hard because: the rule run backwards. (nearest: L05-q9, the Sun version as two options — a different sky, the same move; the quiz item is on the Sun and this one on the stars)

⟂ draw constraints (an item that prints another's answer, or a near-twin pair; the test builder draws one per test)

• PP-1 ⟂ PP-2 (one spin: the HOW LONG set and the hours set). PP-3 ⟂ PP-4 (what we call one spin). PP-8 ⟂ PP-10 (one trip: the set and the age). PP-9 ⟂ PP-43 (what we call one trip, MCQ and typed). PP-42 ⟂ L02's lexicon line in no bank item (orbit is defined only in its own stem).
• PP-17 ⟂ PP-1, PP-2, PP-39 (Andre's hour claim prints "about 24 hours", the answer to the spin items and the typed 24). PP-21 ⟂ PP-8, PP-19, PP-41 (Phoebe's claim prints "about a year"). PP-19 ⟂ PP-41 (the reason prints 365 days).
• PP-22, PP-23, PP-24 (three drawn pairs on one move) — one per test. PP-25 ⟂ PP-26 (the kite watcher and the 2 × 2 form). PP-27 ⟂ PP-32 (a winter pattern in July, two scenes). PP-33, PP-34, PP-35, PP-38 (WHAT IS REALLY MOVING, four scenes) — two per test at most. PP-49 ⟂ PP-36 (both trace the whole sky to one turning thing).
• PP-46 (the notebook) prints "winter … next winter" as its reasoning, the answer to PP-27 and PP-32: never the same test.
• Added in v2 (2 Oct 2026): PP-24 ⟂ PP-26 (the 2 × 2 place-shape form, drawn and undrawn). PP-30 ⟂ PP-32 ⟂ PR-9 (the "up by day, hidden by sunlight" reason, three scenes). PP-42 (typed orbit) ⟂ nothing now: "orbit" is stripped from PP-10 / 18 / 19 and from every option in the bank; L02-q10 stays last in its quiz.

v2 — 2 October 2026 (the fix pass; records/BUILD_RECORD_G4T31.md, v2 section)

Pedro is Andre throughout. Every WHAT IS REALLY MOVING option is a short full sentence, and the stars and Moon stems have their own distractors (the bank's three MOVING* sets). The SPA4-005 block is re-patterned and re-cased (an M, an arrow, a cross; a count of movers; two photos compared; the triangle in January) so no bank drawing or move is L03's with the chips changed. PP-16's key reads "smoothly and steadily". PP-28 / PP-47 key "next summer" / "next winter" against real distractors. Counts unchanged: 52 items, 47 MCQ + 5 typed, keys A 11 · B 12 · C 13 · D 11, tiers 14 / 24 / 14. check_key_tells.py: 0 of 107 flagged.

v3 — 2 October 2026 (the polish after Reader C's full re-read; records/BUILD_RECORD_G4T31.md, v3 section)

Two bank keys matched to their distractors' shape: PP-23 "It has kept its shape as it moved." (type 11; the comma clause is gone) and PP-44 "The stars keep the same shape all night." (type 9; the only "and" is gone). The typed YEAR list no longer accepts "365 days", "12 months" or "twelve months" where the stem asks for the NAME of the time; each gets its own feedback line (YEAR_WRONG), and the quizzes' and practice set's "day" and "year" items do the same for "24 hours". PR-10's watcher is on a boat held still by its anchor (a ship at sea really is moving, so its old distractor was a second true option). No key letter, tag, type or figure changed; check_key_tells.py: 0 of 107 flagged.

Skill: course-build → review-lesson (Roles B, B2) · review-questions · review-accuracy @ fb37d14 — non-author review, filed by the coordinator from the reviewer's report

Topic 31 — guidance, questions and accuracy review, 2 October 2026

A sound topic that teaches the right things at the right depth, with one figure that contradicts its own text and one wrong reason sitting in a key. The science holds: Earth drawn from above the North Pole, the arrow counter-clockwise (right for that view), the lit half on the Sun's side, the dot's path right, the whole-sky card moving the Sun, Moon and stars the same way (left to right facing south), Orion in January and the triangle in July honest for Dallas, "Orion is up in the daytime in July" true, Topics 31 and 32 agree about the Moon. But the spin strip and animation move the red dot round a disc whose land stays still — a town sliding over a fixed Earth, the opposite of "the sticker goes round with the globe". And "Earth spins so smoothly and so slowly that nobody can feel it" (L01 line, L01-q7, PP-16's key) gives the wrong reason: we feel nothing because the motion is steady, not slow. Counts re-perform; one record claim is false ("16 bank items re-scened" — the SPA4-005 block is mostly L03's quiz with nouns changed).

Key-tell checker: KEY TELLS: 10 of 107 MCQs flagged (a: 2, b: 1, c: 7).

Essentials

1. The "what is really moving?" family: every option a full short sentence (set below); PP-34/35 get their own distractors — for the Moon never offer "the Moon is traveling around Earth" (Topic 32 teaches it as true).
2. Spin figures (spin_strip, spin_anim, spin_disc item forms): rotate the land with the dot; only the shading stays toward the Sun.
3. "so slowly that nobody can feel it" → "so smoothly and steadily" in L01's line, forest line 1, L01-q7 fb/why, PP-16 key and why.
4. Topic 30 recall: L05 forest 1, article idea 1, script beat 2, q1 options/fb/why and PP-38 use "rise/set toward" — Topic 30's sentence is below. L05 script: "Every day the Sun comes up in the east and goes down in the west." keeps it at 150.

Worth fixing

1. L04's rule "A pattern you see on winter evenings is gone in summer" is false of the Big Dipper and the W (both in the evening sky all year from Kansas and Dallas). 6. PP-28 "next July" and PP-47 "next January" right only by omission → "next summer" / "next winter". 7. Freshness, SPA4-005 block: PP-12, PP-13, PP-22/23/24, PP-25, PP-26, PP-44 are L03's items renamed; PP-30 = L04-q5 = PR-9 — re-pattern (an arrow, a cross, an M), re-case; ⟂ PP-24/PP-26 and PP-30/PP-32/PR-9. 8. Typed "orbit": keep L02-q10 last; strip "orbit" from L02-q3's stem/fb/why and PP-10/18/19 ("on its path around the Sun"). 9. Accept lists: day + "a whole day", "a day and a night"; year + "12 months", "twelve months", "a whole year"; Earth + "the world", "world", "the planet". 10. Cause before effect in L01/L02/L03 idea lines; L05 "The sky works the same way" is a vague link. 11. Rename Pedro (Paul/Pedro confusable) at the NAMES_POOL row.

Leave

The no-tilt translation; "the clouds pushing the Sun" (Baxter); L04's 7 items; "turn" as the noun for a fraction; PR-1/12–15 reusing quiz stems; "grandmother" in L01-q2.

Author's seven questions: 1 keep (fix the still land). 2 keep — true. 3 keep both; PP-13 → "People who study the stars use another word for a star pattern. What is it?" 4 keep as terms with typed recall; widen accepts. 5 accept — leaves out the turn about the North Star and the arc of southern patterns; Grade 5 adds, never unteaches. 6 yes. 7 fine.

The Topic 30 sentence L05 recalls, word for word: "Every day, the Sun seems to move across the sky on a curved path. It comes up in the east, is highest around midday, and goes down in the west."

Skill: review-figures @ fb37d14 — non-author figure review with the page pass, filed by the coordinator from the reviewer's report

Topic 31 — figure review, 2 October 2026

What a student notices first: the spinning Earth reads at a glance — Sun left, lit half left, one arrow over the top, counter-clockwise, the red town dot going round the right way. The orbit is a clean near-circle, every arrowhead one way. The star pairs make their point without words. Then four visible faults: a strip cut off at its fifth disc, a figure with two red towns, a star pattern drawn on top of the barn, a "JANUARY EVENING" chip hanging off its panel. (The guidance review adds: the land must turn with the dot.)

Fix before a cold read

1. spin_strip — content runs to x=614 in a 600-wide frame: the 24 HOURS disc and chip clipped. Frame 640 or cx = 96 + k*112.
2. spin_anim — spin_disc always draws the still town dot, so the page shows TWO red dots. town=False for the animated form.
3. whole_sky_anim — the KITE sits over the barn and its +60 translate carries stars past the panel onto white; the "0 0 → 60 −30 → 0 0" path swings the sky back the wrong way. Origin ≈ (390, 80); values "0 0; 60 −30"; every star inside 10..570 at both ends.
4. orion_january, seasons_sky — the time chip centred at x0+42 overhangs the panel and frame. sky_panel: chip at x0 + chip_w(label)/2 + 8.
5. orbit_headache — the PEDRO'S BIRTHDAY chip across the dashed orbit; disp=340 beside orbit_months at full width. disp=None; chip at (ex+36, ey+40).
6. Item text under the 13 px floor at phone width: spin letters 9–10 px; orbit letters 9.5–11; q_pick_jk letters and chips 4.7–5.5; pattern-pair time chips 6.4–7.5. A 14 px chip variant for item letters and times; q_pick_jk to two rows in a ≤560 frame.
7. Spin items — the left letter chip sits on the middle sunlight arrow. Drop the middle ray on item forms or chips at R+40.
8. Page (builder, listed once): at 360 px the column renders 418 px wide, so every figure's right 58 px and every two-panel item's right panel is off-screen, stems clipped mid-word. Not a figure fault — the site engine owes a fix before any phone read (coordinator: tell the Grade 3 session; the builder is shared).
9. From the guidance review: spin_strip, spin_anim, spin_letters rotate the land with the dot; shading alone stays toward the Sun.

Page pass

Desktop: every figure renders alone and whole except 1, 3 (and 4's overhang). check_svg_ids.py: 41 figures, 18 ids, 2 shared (g29_14 / g29_15 identical radialGradients) — PASS. Phone: fails on item 8.

Star-shift measurements

Dipper pair (+60,−60); W pair (+60,−60); q_kite_two (+80,−40); pp_w_two (+80,−60); pp_kite_two (+80,−40); pp_dipper_two (+60,−60); q_pick_jk J whole shift, K with the fifth star moved 30 right — the one impossible sky, kept only as the wrong candidate. All move up and right; with no compass drawn this reads as rising. Add "no compass drawn" to the record's simplification note.

Unplaced

None — all 41 placed.

Minor

whole_sky_card bottom band has an unlabelled red dot; Sun:Earth 2.7:1 covered by NOT TO SCALE; the LETTERS comment says orbit letters start "upper right" but 35° is lower right (comment only). Briefs: four lack "the eye must see first" / side (globe_cartoon, birthday_cartoon, car_cartoon, sunrise_photo). Captions never say "real"; no item drawing, alt or blind text names its key.

Best: orbit_months; dipper_two_times; whole_sky_card. Weakest: whole_sky_anim; spin_strip; q_pick_jk.

Skill: course-build → review-lesson (Role A blind key read, two readers; Role C adjudication by the coordinator) @ fb37d14

Topic 31 — The turning Earth and the stars — blind read, 2 October 2026

Every key agreed by two blind readers (120 and 117 rows; MCQ disagreements 0 for both; the six lettered Earth/orbit items and five star-panel shift items checked star by star; typed answers on the lists; the FRQ models match). One real fault, and it is shape: in the whole "what is really moving?" family the key is the only option opening with a capital (Earth / a child's name) while every distractor opens with "the …".

Flags carried into the fix pass

Readers' files: blind/2026-10-02/READER_A.md, READER_B.md.

Skill: review-lesson @ e23b67f — Role A (blind key reader), Reader C, cold read of BLIND_BUNDLE_G4T31.md (v2) only.

Takeaway. Every item has exactly one true option and a strong Grade 4 student can answer every one of them from the stem and the drawing alone. The v1 fault is gone: every option in the "what is really moving?" family is now a full short sentence with a capital and a full stop (L05-02, L05-03, L05-05, L05-V-01, SUMMARY-03, PR-10, PP-33 to PP-35, PP-37). The lettered Earth and orbit drawings all match their stems and none hands over the answer; the star-pattern pairs show the shift without naming the verdict; no Moon item offers "the Moon is travelling around Earth"; the word "orbit" is in no stem before a typed item that asks for it. One item I would hold: PR-10, where a ship at sea is literally "really moving", so a careful child can defend option A. Smaller notes: the L01 quiz opens with five B keys in a row; PP-23's key is the only option carrying a comma clause; PP-44's key is the only option with "and"; "Phoebe" is a hard read for a nine-year-old though it is not confusable with Paul or Andre.

Adversarial answers (typed items)

Cross-item notes

• "What is really moving?" family: every option in L05-02, L05-03, L05-05, L05-V-01, SUMMARY-03, PR-10, PP-33, PP-34, PP-35, PP-37 is now a full sentence with a capital and a full stop. The v1 capital tell is gone. The key sentence "Earth is spinning around." is printed word for word as the key in eight items; a child can learn the string. That is the fluency repetition the format ladder welcomes, so a note, not a fault.
• Lettered drawings (L01-03, L02-03, PP-07, PP-15, PP-18, PP-19): the stem's letter is the one the description places the dot or Earth at; letters are listed in arrow order; no description names where the dot ends up.
• Star-pattern pairs (L03-02, L03-03, PP-22 to PP-24): the descriptions give coordinates only, no verdict word. L03-03's K differs by one star, which is the right size of difference.
• Moon items (L05-06, L05-V-01, SUMMARY-03, PP-35, PP-49): none offers "the Moon is travelling around Earth".
• "orbit": in no stem anywhere; appears as an MCQ option in L02-01 and PR-01/PR-13 before typed L02-10 (same quiz, just coined) but not in any PP item before PP-42.
• Key runs: L01-01 to L01-05 all B; L04-01 to L04-04 all B; L05-01 to L05-04 all A. Adjudicator's S25 call.
• Names: Paul, Andre, Phoebe are distinct at a glance. "Phoebe" is the one a nine-year-old may stumble over (ph, silent-e pattern); not a confusion with the other two.
• Repeats across sets (L01-01 / PR-04 / L01-V-01; L03-05 / PR-13; L01-05 / PR-12; L04-06 / PP-46; L05-04 / PP-48) are fluency re-asks; the PP versions carry fresh scenes.

Would not ship as is: PR-10.