With the Urdu project, for example, Ms. Teal saw that the poems' lines could be encoded in Markov chains, a mathematical tool common in the sciences that is used to model how a system—in this case, the metrical components of an Urdu line—moves, based on its current conditions, into one state or another. (Think a flowchart on steroids and you'll get a good enough idea.) Integrating these chains into Mr. Pue's code cut his run time by some 60 percent.