I enjoyed toying with MakerBlock's OpenSCAD tutorial and seeing what I could do with the simple, heart shape used to demonstrate extrusion. So, this is a box with a lid of the same size that holds onto the box from the inside. It should appear a solid object when closed. I haven't worked out actual dimensions, yet, but there are two variables to play with, height and size. This way, you can choose how deep (height) the box is and how big.