Movable letters, proofreading and translation

Before teaching

• Choose actual school-approved products; read current labels/SDS and school requirements.

• Pilot the chosen hands-on method and document real failures, quantities, timings, drying/release and accessibility.

• Verify equipment, supervision, handling, waste and incident procedures.

• Apply lab-specific fallback whenever procurement, source visibility or safe-transfer conditions cannot be met.

Lab-specific review

• Check each mirrored face, especially P/E/L, and the reverse line orders L–E–P–A–P and L–T–A–M–A.

• Use a separately labeled deliberate classroom error if the first proof is already correct; never alter the historical source to manufacture an error.

• Do not extend the Nahuatl word list or fabricate modern translations by analogy.

Teacher preparation

Preparation allowance: 45–60 minutes with verified ready-made sets; allow an additional 2–3 hours if fabricating 120 blocks. Those estimates need local testing. One demonstration set plus paper tiles is a valid lower-material alternative.

Each pair requires P × 2, A × 3, E × 1, L × 2, M × 1, T × 1. Prepare mirrored faces on uniform-height mounts. Test P, E, and L particularly; symmetrical-looking letters can conceal a faulty preparation method. Both the order within each line and the individual glyph shapes must be reversed. The line PAPEL remains above AMATL after horizontal reflection.

Check that the two lines fit the board and that removable mounting prevents sliding without creating uneven height. Prepare a correct proof and a clearly labeled modern error proof. Never change the historical source card to manufacture a mistake.

A pressure problem should not be “corrected” by asking a student to force a lower block into contact. Inspect the block height. Let students correct a transposition without remaking the entire composition, and preserve the earlier proof as evidence.

Redistribution belongs in the lesson. Missing blocks and ink trapped in storage trays affect the next group's work. Count the complete set at both ends of the session.

Access: A student can compose with large paper tiles, direct the block order, compare proofs verbally, or document the correction. Exact paper and block inventories are available for tactile checking. Do not require Nahuatl knowledge beyond the credited reference.

Schedule and equipment queues

Period 1: 10 minutes source reading; 8 reversal demonstration; 17 composition; 8 first proof; 7 cleanup/annotation.

Period 2: 8 minutes peer proofreading; 12 correction/reproof; 12 two consistent impressions and role switch; 8 cleanup/type distribution; 10 evidence discussion.

Alternative material plans

One demonstration set and student composition tiles

• Teacher reversed-block set

  1 10-letter set · class

  P2 A3 E1 L2 M1 T1, all equally high and mirrored

• Paper letter-tile sets

  12 10-letter sets · class

  Same inventory; one per pair

Teacher demonstration only; students compose/correct paper tiles. No individual printed products promised; this is not sequential stamping passed off as a secured forme.

Editorial corrections

The current student procedure is the teaching baseline.

Safety and stop conditions

Read these controls with the teacher before handling materials. Chemical etching is historical context only; the practical intaglio activity uses drypoint without mordants.

Controls

• Class of 24, working as 12 pairs; six washable workstations, each shared by two pairs.

• Room has handwashing, stable tables, drying space, accessible routes, and a teacher who can supervise the chosen tools.

• The drypoint option assumes one proper, maintained etching press operated only by a trained adult under the school's procedures. A no-press alternate is described separately and must be piloted.

• Sizes and stock estimates are intentionally small. Scale consumables by student count divided by 24, rounding upward. Equipment quantities depend on throughput, not simply headcount.

• No food or drink. Aprons are protective workwear, not proof that a product is safe. Read current product labels and safety data sheets; follow the school's risk assessment and disposal rules. The CPSC guide is a general starting point, not a substitute for local approval. [S1]

• Maintain separate clean-paper, ink, and wet-cleanup zones. Cover tables. Take ink residues off tools with scrap first; dispose of residues according to school policy before washing. Do not assume “water-washable” authorizes pouring concentrated ink into a sink.

• Students may work as designer, recorder, proofreader, or paper handler when a physical operation is inaccessible. Participation and historical reasoning must not depend on grip strength or speed.

• Photograph only student work and hands when school permission permits. Do not publish names or images without the school's normal consent process.

Stop when

• Unknown or unsuitable product, missing risk assessment, damaged tool/material, unsafe station, discomfort, or failed actual-stock pilot: pause and use approved alternatives.

• Queue or cleanup time exceeds safe schedule: extend the lesson rather than rush.

Trained adult only

• Teacher pre-cuts stock, selects actual products and SDS, approves setup and waste management, and pilots transfer.

• Cut/fabricate reversed glyph blocks and check equal-height mounts; do not respond to a low letter by forcing the baren.

Excluded activities

• Student carving knives/gouges in the foam and movable-block exercises.

• Chemical etching baths, household-acid substitutes, electro-etching, solvent grounds, improvised press machinery, and experiments on original heritage materials.

Cultural and source review

Specific specialist/practitioner review or permission is needed before claiming cultural endorsement or expanding into community-specific or restricted practice. No paid review, purchase, or spending is imposed as a blanket release gate for these explicitly labeled ordinary classroom adaptations. Do not claim any such consultation has occurred.