By the end of this session, you can…
- LO 7.1Build a paper prototype of one loop from your D2 in under 25 minutes.
- LO 7.2Run a 5-minute playtest cycle with a peer-as-proxy; observe silently.
- LO 7.3Revise the prototype in under 10 minutes based on one specific observation — not everything you saw.
- LO 7.4Repeat the build–play–revise cycle three times in a single session.
- LO 7.5Submit D3: the surviving version + facilitator guide v0.3 + a one-paragraph "what I cut" note.
The cheapest disproof
Every hour you spend in an engine before a loop exists on paper costs you roughly twenty hours in rework later. Paper is not a charming pedagogical exercise — it is the most efficient instrument you have for disproving a loop while disproof is still cheap.
No laptops during build
The temptation to prematurely formalize is too strong. Index cards, markers, tokens, a timer. That is the toolkit today.
One loop, not a game
You are prototyping the single loop from your D2 that carries the most risk (see Session 04 star). Not the meta-structure. Not the narrative. The loop.
Silent observation
When you run a cycle, you do not coach, clarify, or defend. You observe. You write down exactly what the player did and said. You will hate this.
Build–play–revise, three times
| Time | Activity | Deliverable |
|---|---|---|
| 00:00–25:00 | Build v0.1. Cards, rules on an index card, one token type per mechanic. | A runnable prototype. |
| 25:00–35:00 | Play cycle 1 with a peer-as-proxy. You facilitate silently. Peer plays the loop once. | Observation notes. |
| 35:00–45:00 | Revise — pick ONE observation. Change ONE thing. | v0.2. |
| 45:00–60:00 | Play cycle 2. Different peer if possible. | Observation notes. |
| 60:00–80:00 | Revise — again, one observation, one change. | v0.3. |
| 80:00–95:00 | Play cycle 3. | Observation notes. |
| 95:00–115:00 | Final revision pass. Write the "what I cut" paragraph. | v0.4 — this is D3. |
| 115:00–180:00 | Gallery walk; run the strongest loops for the full room; cross-critique. | Peer feedback log. |
The most common mistake is changing three things between cycles. When cycle 2 then goes badly, you cannot tell which change caused what. Change one thing. The others go on the "for later" list.
What to write down
While your peer plays, write on a single sheet. Four columns, pen only. You will be tempted to interpret — resist. Interpretation happens in the revise window, not during play.
| Column | What it captures | What it is not |
|---|---|---|
| Time | Clock at the moment of the observation. | — |
| Did | The specific action the player took. | Not what you wish they had done. |
| Said | Verbatim quote — even a fragment. | Not paraphrase. Not interpretation. |
| Stuck? | Y/N flag if the player paused > 10s or asked a rules question. | Not a severity score. Just Y or N. |
Design is subtraction
D3 submission includes a one-paragraph note on what you removed between v0.1 and v0.4. This is graded. A prototype that grew between cycles is suspicious. A prototype that shrank is almost always stronger.
From The On-Call, v0.1 → v0.4
"Cycle 1 had four token types (evidence, time, fatigue, trust). Playtester spent 3 of 5 minutes tracking tokens rather than deciding. v0.2 cut fatigue entirely and merged trust into a single end-of-scenario score. Cycle 2 still stalled on the evidence deck; v0.3 replaced the deck with a face-up shared pile. Cycle 3 ran in 4:20 with the discrimination objective clearly visible in player decisions. Net cut: two mechanics, one ruleset page, one component type."