The thesis mismatch experiment, online (PLAN.md §8). A shape appears; two sounds play. One is the shape's true Sonarium voice, the other belongs to its opposite (roundness inverted). Which sound is this shape? Your answers measure whether the Kiki/Bouba weave actually holds — data stays in your browser, exportable as JSON.
Method: 2AFC, roundness ∈ {0, ⅓, ⅔, 1}, random size & assignment per round. Success criterion (PLAN RQ1): >70% agreement. Headphones recommended.