One of the first standard methods for generating pseudorandom numbers was to multiply each number in your sequence by a large multiplier K then divide the answer by a different number M and keep the remainder as your next pseudorandom term. This was used by almost all early computers, until George Marsaglia, a mathematician at Boeing Scientific Research Laboratories, spotted a fatal flaw in 1968. If you took the sequence of random numbers coming out and plotted them as coordinates on a graph, they would line up. Admittedly, this could require complicated graphs with upward of ten dimensions.
