Let's go back several years, to the days when there were no Boris Bikes. Imagine that you're a junior developer (congratulations! That was easy). Transport for London, the body responsible for delivery of a new bike system, come to you with a plan: a network of Docking Stations and bikes that anyone can use. They want you to build a program that will run all the Docking Stations, simulate all the Bikes, and emulate all the infrastructure (vans, repair staff, and so on) required to make their dream a reality. They call it - guess what? - 'Boris' Bikes, and they're offering a tasty sum of money.