Calvin's Inventions

Calvin's cardboard box could be the box that he got in a Beanie prize event hosted by Chocolate Covered Sugar Bombs. However, it seems unlikely because the Beanie box is smaller (but it's folded) then any of Calvin's inventions, and one of his inventions were already introduced before the Beanie event.

Here are most of Calvin's inventions.
 * Right side up & top open: Time Machine: A machine that allows people to travel forward and backwards in time. Vortex glasses are always worn.
 * On its side: Duplicator: A machine that clones the person inside.
 * Upside down & top open and on bottom: Transmogrifier: A machine that transmogrifies (transforms) the person inside.
 * Cerebral Enhance-o-Tron: A cone thing that is hooked to a cardboard box with three wires (input, output, ground). It gives someone temporary super-intelligence and makes their head larger.
 * Writer's Block: A large, heavy cube made of wood or may be a cardboard box. Its purpose is to place it on a desk so the writer can't right on it anymore. Hobbes merely does a side glance and dismisses it. It only appeared once.
 * Invisible Cretinizer: An invisible thing causes stupidity in the target. It may be small, because he is seen holding it with only his thumb and his index finger. It was only shown once, when he brought it to show-and-tell. He fired it at Ronald, one of his classmates, and Ronald immediately heckled him. Calvin shows this as proof that it even works at long range.