A pentomino consists of five equal-sized squares attached edge-edge to form some shape. There are twelve possible pentominos that can be formed in this way (plus their reflections and rotations). In this program, each piece is represented by a different color.
Consider an 8-by-8 board, consisting of 64 squares. If you select four squares, can the remaining 60 squares be filled in with the twelve pentominos? The Java applet (which you see below if your Web browser supports Java) will try to solve this puzzle. Select four squares by clicking on them.

Written by David Eck (eck@hws.edu), based on a similar program I wrote for Macintosh.
You can read the source code for this applet. In case you are interested, it illustrates a recursive backtracking algorithm that runs in its own thread.

zur Lösung Pentominos für 10x6 Board