A “quadro” puzzle dates back to the 1800s. I've seen some variations of this online & getting sold on Etsy so I made my own. Classic “fit the shapes into the box” puzzle. This one requires subtle manipulation of the blocks. Not too difficult and fun to figure out. Slide the each block into the box fitting all six shapes without removing the lid. An easy print with no overhangs.

Note that you should print 6 copies of the Blocks shape.