I've been recently playing a game called Approximately Up. You start from simple building blocks, thrusters and can use the in game logic system to build complex controls. One of the things I came about to learn was something to make a hover system for my ship was a simple PID controller. The side and bottom firing thrusters just remind me of my ship in the game. While the game is oversimplified and a bit arcadey, does anyone know what actually goes into this in the real life and is the huge feat the improvement on the weight of the whole car?