Jessica Kerr is a symmathecist, in the medium of code. She believes in learning systems made of learning parts: enthusiastic people and evolving software. She is a Principal Developer Advocate at Honeycomb.io, where she teaches developers to make their software teach them what’s going on inside. In twenty years of professional software development, she has programmed in and spoken at conferences about Java, Scala, Clojure, TypeScript, Ruby, and Elm. She lives in St. Louis, MO with two children who invent worlds and draw characters with superpowers, and two cats who meow and knock over water glasses.