By adding friction to an otherwise limitless activity, you get a game – and with hugball, each different friction added over the years created a different sport. You can’t use your hands: football. You have to stop play between each tackle: American football. You can only pass the ball backwards, but you can kick forwards: rugby. In football, not being able to touch the ball with your hands opens the game up and spreads the players around the field, creating a fluid and constantly shifting playing area that resists rigid strategy and defies statistical models. In American football, the friction leads to a rather stilted game where tactics have to be carefully pre-planned. Rugby, though, is one of the most fascinating sports from a game design standpoint. The core friction of being forced to pass backwards when you need to go forwards creates a fundamental tension that is released when someone makes a great run, a strong hit – or a perfectly weighted kick forward resulting in a moment of chaos followed by relief or jubilation.