1. Thinkengine on github. https://github.com/DeMaCS-UNICAL/ThinkEngine
2. Unity 3d game engine. https://unity3d.com/unity
3. Unity, order of execution for event functions. https://docs.unity3d.com/Manual/ExecutionOrder.html
4. Black & White (2001). https://www.ea.com/games/black-and-white
5. Halo (2001). https://www.xbox.com/en-US/games/halo