Sealed within a transparent, tapered, liquid-filled cylinder, illuminated colored globs slowly rise and fall. Meandering and deforming, their shapes and paths change unpredictably. Invented in 1963, a decorative fixture in many homes during the 1970s, and still in production, Lava Lite lamps are now the object of renewed curiosity.
Indeed, researchers have come up with a novel application of the mesmerizing movements of the lamps globules. They use them as the starting point for generating a sequence of random numbers. Called lavarand, the random-number generator is the tongue-in-cheek work of Robert G. Mende Jr., Landon Curt Noll, and Sanjeev Sisodiya of Silicon Graphics in Mountain View, Calif. (see http://lavarand.sgi.com/).