Penta people, the Pentominoes, always build their houses from five
square rooms. I wonder how many different Penta homes you can
Can you make these equilateral triangles fit together to cover the
paper without any gaps between them? Can you tessellate isosceles
A tetromino is made up of four squares joined edge to edge. Can
this tetromino, together with 15 copies of itself, be used to cover
an eight by eight chessboard?