Squares all the same size, counted wherever their middle is inside: 208 in the blue ring, 208 in the green disc.
Bigger or smaller?
Bullseye illusion
Which has more color in it, the green disc or the blue ring?
Neither: they have the same area, though the green disc looks much bigger.
Why? The ring is spread out thin around the edge, and your eye judges a shape by how wide it looks, not by how much there is of it. Cut the blue ring up and it would exactly cover the green disc.
Picture: Mabit1, CC BY-SA 4.0 · Wikipedia(opens in a new tab)