Tesseract

A friend of mine, MC, who is rather mathematically inclined sent me this picture of a rotating tesseract.

http://upload.wikimedia.org/wikipedia/en/d/d7/8-cell.gif

Note from Wikipedia: "In geometry, the tesseract, also called 8-cell or octachoron, is the four-dimensional analog of the (three-dimensional) cube, where motion along the fourth dimension is often a representation for bounded transformations of the cube through time."