Inspired by the Easy as PI box (http://www.thingiverse.com/thing:3817) and the A-Mazing Box (http://www.thingiverse.com/thing:1481). The combo is as easy as PI... to 15 figures.

That's 3.14159265358979

Print one of each piece. Snap Ring3 onto the Base, Ring2 onto Ring3 and Ring1 onto Ring2. The ticks are 0 to 9, so remember that 3 is actually the fourth tick, 1 is the second tick etc.

Align the ticks to the first three digits (314) from left to right with the Base all the way to the left and the lid to the right. Advance the lid out one stage. Repeat for the next three digits and so on until the lid comes free.

When in trouble, unsnap the Base from Ring3 to access the contents.

Some sanding is required to get everything to fit smoothly.