A Tetris Figure is every figure in the plane which consists of 4 unit squares connected by their sides (and don’t overlap). Two Tetris Figures are the same if one can be rotated in the plane to become the other.
a) Prove that there exist exactly 7 different Tetris Figures.
b) Is it possible to fill a 4×7 rectangle by using once each of the 7 different Tetris Figures? combinatoricsgeometryrectangle