Lavarand

Lavarand was a hardware random number generator designed by Silicon Graphics 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 secondary part of the random number generation uses a pseudo-random number generator, the full process essentially qualifies as a "true" random number generator due to the random seed that is used.