I make and sell wooden bandsawn puzzles (when I'm not at work writing software). My favorite is my "Wedge Key" puzzle that looks like a trivial 4 piece puzzle, yet will not come apart until you figure out just the right twist. I also make an "Impossible" puzzle that will never come apart. Another is my "27 piece cube" that interlocks in all three axes at once.
Send me your US Mailing address, and I'll send you a brochure/price list.
Keith Winegar 4539 Oakleaf Drive Vadnais Heights, MN 55127, USA
A similar impossible interlocking puzzle is 'Quartet'.
A version not in wood was made by Binary Arts. It was sold together with the 4 T puzzle.
Bill Cutler Puzzles, Inc. 405 Balsam Lane, Palatine, IL 60067, USA 847/705-1186