7

Part of 2008 Switzerland - Final Round

Problems(1)

21 parts of 8x11 rectangle

Source: Switzerland - 2008 Swiss MO Final Round p7

8 \times 11

rectangle of unit squares somehow becomes disassembled into

21

contiguous parts . Prove that at least two of these parts, except for rotations and reflections have the same shape.

tilesTilingcombinatoricsgeometryrectangle