Track your mouse and keyboard activity separately for each game, allowing you to render high quality images in the colours of your choice.
It is designed to run quietly in the background, and has features in place to ensure the results still look interesting even after hundreds of hours.
The full Python source code is available on github.
Anyone is welcome to have a go at tweaking it, though please get in touch if you are either able to translate for your own language, or have some experience coding in Mac/Linux.