Watch a masked ball trace a hidden path, then select all matching trajectories from the grid. The ball is only visible through temporal motion integration; blind guessing succeeds ~0.2% of the time.
This is a client-side preview so you can experience each check. Inside a real Carrier experiment, challenges are generated server-side, answers are verified server-side and never appear in any client payload, and every result is recorded on the participant's run and interleaved into the session transcript.