Each dimension has to be 1" or bigger, otherwise the cube won't fit. _________ WAIT ! The container doesn't have to be rectangular, and that opens up a lot more possibilities. The smallest possible rectangular container is a little tiny cardboard cube whose dimensions are all 1", just like the contents. But you could also keep it in a container shaped like a pyramid, a cylinder, an egg, etc. If the container is a sphere, then its radius has to be at least 0.866 inch.