Cities: Skylines is Turing Complete

(Non-clickbait title: building a 4-bit adder in Cities:Skylines.)Cities: Skylines is a city simulation game that is complex enough to build universal logic gates in it. The buildings are placed far apart because otherwise power would freely flow between them.We need one more component for functional completeness: an inverter, or NOT gate. Fortunately power lines can cross each other without intersection if there is a sufficient height difference.Finally, I needed to build a city nearby that produces enough sewage to flood up to 8 wind turbines at the same time. Due to how power is implemented in the game, components of a gate need to be placed relatively far apart, otherwise power would flow between them.