1 FRAME
Perception Threshold Test
A 2-digit number hides in visual noise for exactly 1 frame (~17ms).
20 levels across 4 phases
Phase 1 — 6 frames → 2 frames (~100ms → ~33ms)
Phase 2 — Random position · dimmer · down to 1 frame
Phase 3 — Ghost decoys appear · 8 choices
Phase 4 — Ghosts = target brightness · 16px
❤️❤️❤️ 3 lives · No continues