Nine Squares - G4G9 puzzle

For the Ninth Gathering For Gardner I designed an appropriate exchange gift. It consists of 9 pieces, 3 different kind of pieces (all square), 3 copies of each kind. Additionally, it had to be cheap to produce (as 300 copies were required). Therefore, all pieces had to be planar and producable on my lasercutting machine in a reasonable amount of time. After a much thinking I decided that the puzzle whould look like this.

The puzzle is based on a 11x11x11 grid. Each piece is based on a 11x11 grid. I tested many shapes, but eventually settled on the following set:

This set has a couple of very nice properties:

• There is only one solution
• The puzzle does not fall apart too easily (it is a level 3 puzzle meaning that the first piece comes out on the third move)

Solution of the puzzle

Download BurrTools for your operating system and download the puzzle definition file. Open the file with BurrTools, select the tab Solver and drag the slider under Move to see how the puzzle is taken apart and put back together again. Rotate the view by dragging in the image on the right.
The log files of this web server are stored for a loooong time, so you may want to think twice before you download the solution. Solving it yourself is so much nicer.

Peter Knoppers