A gyricon or rotating-particle display having an "eggcrate" substrate. The display includes a substrate having a cavity-containing matrix whose cavities are disposed substantially in a single layer and are arranged within the matrix substantially in a geometrically regular pattern, and a plurality...http://www.google.com/patents/US5815306?utm_source=gb-gplus-sharePatent US5815306 - "Eggcrate" substrate for a twisting ball display
