How to play
Choose either hand, left or right; select a wave, circle, figure eight or number 2; then choose a wide, medium or narrow tracing path. Touch or mouse is the default. Optional camera mode privately tracks an index fingertip after a six-second comfortable-range calibration.
Move along the pale guide. The path turns turquoise as it is covered, while your pink stroke creates a blue mirrored ribbon on the other side. Coverage measures how much of the guide you visited; accuracy reflects how often you stayed inside the selected width. The five speeds change the moving guide spark, not the score tolerance.
Safety boundary
Use a stable seated or supported standing position and do not reach to your limit. Stop immediately for pain, dizziness, breathlessness or unusual fatigue; the safety-stop result earns no score or reward. Camera processing remains in the browser and stores neither video nor landmarks. This is general activity, not medical measurement, treatment, rehabilitation prescription or outcome assessment.