Missing (or Extra) Square Optical Illusion

piece size

1

transform

0

rearrangement

layout 1

layout 2

grid

apparent area = 13 × 13 = 169

Four pieces of a square are rearranged to create a rectangle that appears to have a different area than the original square. Rearranging the pieces with a second layout forms three rectangles that also seem to have a different total area. The change in area is caused by a slight overlap or gap along a diagonal that becomes more apparent with smaller pieces.