Calibron 12

The objective is to make a square and fit them into the large opening of the puzzle. There is only 1 solution and it is very difficult to find.  We packaged the puzzle unsolved, but the solution is provided.  In the frame there is an extra space to hold one of the pieces so that it could be packaged unsolved.  Our version is made from precision cut woods with at least 4 different woods in each puzzle. Ash, Maple, Walnut, Oak, Mahogany, Birch, Cherry, Alder, and other woods may be used with each puzzle have a little unique look.  The pieces are very strong at 1/4" thick and have a nice finish.  We also laser engraved the relative size of each piece on the piece itself, which may be helpful to you folks who want to attack this analytically.  It also makes identifying the pieces easier if you just want to use the instructions to solve it.  

Puzzle measures 9" x 7" in the base.  The square opening is about 6.3" x 6.3".