WOLFRAM|DEMONSTRATIONS PROJECT

Missing (or Extra) Square Optical Illusion

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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.