Sandro del Prete

The fourth dimension has yet to be defined. This illustration represents the illusion of a fourth dimension by neutralizing the directional notions of "front" and "back". Thus, the viewer has the impression that all the corners are at the back, though logically, this cannot be. In this gateway to the fourth dimension, the suggestive effect is so powerful that one almost feels the two shorter crossbars curving back in an arch.