Wooden brain teaser puzzle box where the object is to fill all of the pieces in the square. There is only one way to accomplish that, and any variation may get you close, but you will probably hit a snag on the last piece. This puzzle was originally designed by Thomas Edison's son, Theodore in 1933. This puzzle comes unsolved, but directions are included, if you choose not to spend the time to solve it yourself. A variety of woods are used, which makes for an attractive product.