See the first post in The Pragmatic Programmer 20th Anniversary Edition series for an introduction. Challenge 1 Time for a little quantum mechanics with Schrödinger’s cat. Suppose you have a cat in a closed box, along with a radioactive particle. The particle has exactly a 50% chance of fissioning into two. If it does, the cat will be killed. If it doesn’t, the cat will be okay. So, is the cat dead or alive?