Here's food for thought: One of the more intriguing types of algorithm is the genetic algorithm. Genetic algorithms mimic Darwinian natural selection, where "fitness" selects individuals for survival, breeding, and, hence, adaptive mutation. "Genetic algorithms applied with Perl" covered the background on this, and provided two Perl implementations, one that bred bytes and another that bred words. This follow-up article( "Genetic algorithms, the next generation" ) expands this idea of Perl evolution with more advanced material on genetic algorithms.