The tips of the gecko's toes are covered with corrugations of fantastic complexity. The corrugations are lines of tiny hairs. Flattened in the right way against a surface, the hairs lie so tightly on the surface that the gecko's toes literally form a kind of chemical bond with it. (In technical terms, the gecko takes advantage of van der Waals force.) This is a phenomenon that intrigues researcher Alan DiPietro, of iRobot, in Somerville, MA. Clinging to the glass wall of a terrarium opposite a real gecko, DiPietro's crude, 13-centimeter-long, 100-gram Mecho-gecko has sticky feet that let it clumsily cling to walls, at least for short intervals. From the book Robo sapiens: Evolution of a New Species, page 92-93.