Smallest

tap the smallest ball. the rings lie.

balls in rings of different sizes: tap the smallest before the bar runs out, while the rings make the small ones look big; streaks multiply your points

The same ball looks bigger in a tight ring and smaller in a wide one (the Delboeuf illusion). A ring changes how big a ball looks, never how big it is, so the smallest ball is always the answer, whatever ring it is in.

Concepts: perception, vision, scale, attention.

An interactive you play with one thumb, on Wundr.