Are the two shapes the same (rotated) or different (mirrored)?
Two shapes appear side by side.
The right shape is either the left shape rotated (SAME) or its mirror image (DIFFERENT).
Tap SAME or DIFFERENT before the time bar at the top runs out. A correct guess extends your streak; a wrong guess OR running out of time ends the game. The time limit shrinks as your streak grows.
Goal: longest streak.
This is a mental-rotation test, and the fast way to read it is to ignore the shape as a whole and lock onto one telltale feature. Find an asymmetric detail — a notch, a tail, the limb that points off at an odd angle — and ask only what happens to that one feature. If you can spin the left shape in your head and that detail lands where the right shape has it, they are the SAME.
The giveaway of a mirror is "handedness": a rotated shape keeps the same chirality, like turning a right hand, while a mirrored one flips it into a left hand no amount of turning can fix. When the timer is tight, trust the first clean read — if a feature that should be on the inside of a curve is suddenly on the outside, it is DIFFERENT, and second-guessing a correct snap judgement is how streaks die.