Pentomino
a polygon in the plane made of 5 equal-sized squares connected edge-to-edge / From Wikipedia, the free encyclopedia
A pentomino is a 2D shape made out of 5 side-by-side equal-sized squares. They can be found in the books Chasing Vermeer and The Wright 3. It was created by Solomon W. Golomb.
These are the 12 pentominos: