 Since 2012, Munroe has been answering unusual questions sent in by readers of xkcd on his blog What If ?. The concept was inspired by a weekend program organized by the Massachusetts Institute of Technology in which volunteers can teach classes to groups of high school students on any chosen subject. Munroe signed up after hearing about it from a friend and decided to teach a class on energy. Though the lecture felt "dry" at first, once Munroe started bringing up examples from Star Wars and The Lord of the Rings, the students became more excited. The entire second half of the class was eventually spent solving mathematical and physics problems. Munroe wrote the first entries a few years before the start of the blog, based on questions he was asked that day.
