Here's a puzzle i played as a little tyke at my Grandpa's... Made by stacking 2 3/32" sheets (from colorado heirloom). One of them was vectored/engraved. (the piece in the lower middle is missing, to allow the pieces to shuffle around). In the pic, you'll see the pieces aren't in the same config as when cut (grain different) but the pieces slide a lot better if you leave them in the same orientation as when cut. Mine slide just fine in the Maple piece just using the Kerf (without making the pieces slightly smaller).
It's FUN
Here's the Ver 9 CDR
if you're interested.
Next is the 15 little squares with numbers and you shuffle around rearranging the numbers.
Shaddy.