Simple Mystery Box Set

So my daughter turned 3 and she loves tools and "fixing things" (aka taking apart everything)

So I made this simple box, fastened shut with 16mm nuts on m10 studs.
If you need the stud or the nut, they are made to actual m10/16mm specs.

Closed it up with one of her favorite little blind toys, and left the wrench nearby...

The outer dimensions of the box are 76mm cubed,
It will fit something about 46W x 46D x 64H inside the posts, 
with extra room between them.

I feel like this would be a fun thing to remix with the mario question block or something...