Hi all, You know that I like when a box can be closed by a lid that is identical to the box itself (see this topic). So for the Maryland Plastics injection molding contest, I propose a container that follows this rule, the Dod Box The basic shape is half a dodecahedron: take a dodecahedron standing on a flat surface and keep only the 6 lowest faces. All the difficulty has been first to allow this container to be closed with exactly the same shape (with a tab system), and second to make these boxes stackable. This the result: The diameter of the dodecahedron is 25 cm, the thickness of the walls is 3 mm, the clearances are 0.5 mm (+/- 0.25 mm to be exact). When it is closed, you get back the regular dodecahedron shape. You can maintained the box closed thanks to a large rubber band (to carry food for a picnic, for instance). In this last rendering you can see how you can stack them, in closed or opened position. Sorry for the poor rendering, it is not easy to render transparent plastic. I used colors so that you can distinguish the different parts. As usual, your feedback is welcomed!