Free browser game
Four corners. One stroke. Straight lines are deceptively hard — your hand wants to curve. Prove your geometry instincts are as sharp as the angles you're trying to hit.
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Top scores
How to play
Press and hold to trace the ghost square in one continuous stroke — all four sides, back to where you started. Release to score. The algorithm measures side straightness, corner sharpness, and equal side lengths.
Tip: slow down at the corners. Rushing through 90° turns is the most common reason scores drop.