I design my wooden puzzles from basic geometric shapes. The latest, the football ( called a prolate spheroid of all things), is quite a unique shape from a puzzle designer standpoint ... quite the challenge to develop into a puzzle!

In my early years of constructing wooden puzzles, the wood I used extensively for my puzzles was Canadian eastern yellow birch which I've found to have exceptional qualities for puzzle making.

The brown staining effect comes from a fungal disease especially if the tree is subjected to poor drainage (swamp areas). The streaking effect comes from the bronze birch borer larva tunneling through the wood.

For the tessellated effect in the checkerboard puzzle I used African mansonia walnut which unlike North American walnut has a straighter grain and produces a more even cube for puzzle construction.

And the wooden cube must be accurate - tolerances of .005 inch at best.

Even then, there is the humidity factor ...