Design decisions
Answers that make sense.
The first version generated sentences word by word with a Markov chain. With a small, poetic corpus it produced broken grammar that read as noise. The final version chooses complete lines and puts the intelligence into the selection, so every answer is legible and feels aimed at the person.
One surface, not layers.
The water, the drifting particles, and the letters are all driven by the same ripple simulation, so the hand's wake bends everything together instead of sitting on top of it.
Answers made of the water.
For each letter of the answer, the nearest matching letter already flowing in the stream is pulled into place. The answer is literally assembled from the current, then released back into it.
Feedback within a second.
Testing showed that a silent pause after a pinch felt broken. The reading phase, a gold highlight, and a soft chime now confirm the gesture immediately.
Sound without files.
All audio is synthesized live in the browser: water and a swish that follows hand speed, a pad, chimes for each trait, and a bell whose pitch rises with the match score.