Perfect Circle
Draw a circle around the center dot. Your stroke is graded as you draw — it turns green when you hug the ideal radius, amber as you start to drift, and red when you stray far off.
Draw slowly and your hand shakes; draw fast and your radius wobbles. Anything above 95% is a genuinely good circle. Your best score is saved in this browser.
How scoring works
The score combines the stroke's mean radius, radial deviation, and angular coverage around the center. Connecting the start and end points is not enough: a high score requires a consistent radius and a nearly complete turn.
Stroke color shows the live radial error at each point. The result panel reports mean radius, deviation, and coverage, while your personal best stays only in this browser's local storage for the next attempt.