Lavarand was Silicon Graphics' name for its hardware random number generator that worked by taking pictures of the patterns made by the floating material in lava lamps, extracting random data from the pictures, and using the result to seed a pseudo-random number generator. Although the second part of the number generation uses a pseudo-random number generator, it's a "true" random number generator due to the random seed that's used. It's covered under, titled "Method for seeding a pseudo-random… (More on Lavarand)