A live demo of the spec. One deterministic field, two observers, replays as proof.
Drive with W / A / D (or arrow keys). Click the canvas first to give it focus.
What each part demonstrates from the spec:
• Two panels, one world — Evolution runs once; Observation is detached and duplicated. (C2)
• Record → Replay — the world re-evolves from the input log alone; the state hash matches bit-for-bit. Replays are the canary. (C3)
• Wake — a cosmetic layer using randomness, excluded from the hash. It looks different on every replay while the ships stay identical. (C4)
• Show field data — the truth is the integer field on the left; the water you see is only a reconstructed observation of it. (C1, C5)