Pentominoes

Aim - to put the 12 Pentominoes in the selected area. These are the unique shapes made up of five regular squares - defined originally by Solomon W Golomb in 1953 - and feature in Arthur C Clarke's book Imperial Earth. Henry Dudeney included in his 1907 book The Canterbury Puzzles the earliest puzzle using a full set of pentominoes.

You specify how many solutions to search for - by default 1. Note this can take time.

Backtracking is used to solve the puzzle : the program tries to place an unused pentomino in the next free position, and if successful tries to place one in the next position. If it cant place one in that position the current choice must be wrong so it is removed and another unused one is sought.

If 1 solution : press ShowMoves to see how it is solved - using backtracking. Use the slider to change the animation speed.

If many solutions - press ShowSolns to see them in turn.

You can select different areas of 60 squares to fill.

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