10 Penny Puzzle

Small hardwood scrap maybe 5" x 6".

Shaper Origin 1/4" bit.

My file cut just a wee bit too small from file. The recess needs to be exactly 2.53" square. Good thing SO can sneak up on exact dimensions. Just set negative offset and cut until pennies just barely fit in recess using pattern from solution picture. I set depth to .07" so penny is nearly flush. NOTE: Can be done with other coins. The magic number is 3.38. Multiply coin diameter by 3.38 to get dimensions of recess. Again, you may have to add a couple of thousandths depending on moisture of wood.