Why Fispheebox ?
Five sphere box boolean.

This box is very resistant, when this box is closed, it's very hermetic, i modeled solid join connection all around, so you need pressure to hear the "clack" of the oping box. i've not tested yet, but i think this box can float on water.

Modeled with 3DSMAX. 5 Spheres with 128 sections boolean and shell. I after modeled join to clips the two half pieces.