Goal: order the three pictured positions and name one movement detail missing between them. Proposed codes: AC9SFU02 (representation only), AC9SFH01, AC9SFI03. Prepare: three stills, F's exact text, Card 121.
- Source · 3 min. Display FICTIONAL MODEL F; keep any actual-class result line marked REAL OBSERVATION NOT AVAILABLE.
- Look/read · 4 min. Point or read START left, MIDDLE centre, FINISH right. Name the same square in each frame without adding an arrow.
- Adult model · 5 min. Say “I can see three positions. I cannot see the whole movement between these pictures.” Show a closed hand over the gap, not a pretend result.
- Child try · 7 min. Card 121 routes order all three and state or select one unseen detail: route, pause, lift or speed. Scribe exact first wording.
- Probe · 4 min. Ask, “Would these three stills prove the square never stopped?” Invite a source-bounded correction.
- Exit · 2 min. Save source MODEL, ordered positions and the child's unknown. Do not credit real movement observation.