Challenge : Make a solver for the Pentominoes puzzle.

This probably requires a recursive backtracking algorithm.

The field can be 6x10 ; 5x12 ; 4x15 or even 3x20 squares
The standard 6x10 field has 2048 distinct solutions (if i remember correct) not counting the horizontal and vertical symmetry solutions.

Rotation and flipping of the pentomino pieces can be a problem (unless you make a different piece for each orientation but that takes a lot of code)