Reproduced from a wooden burr puzzle given to me as a gift. The two-part pieces are my own design that snap together when assembled as part of the puzzle.
Print two copies of the STL file to make all the pieces for the puzzle. They are vertically stacked because laying them out flat takes too much space and will warp on a standard Makerbot.
It takes about four hours total to print, but will give you endless* fun trying to put it together.
To separate the vertically stacked pieces, just bend the stacks at the meeting points; the joints holding them together should be weak enough to come apart. If not, slip a utility knife in there, being careful not to cut yourself.