The Vectrex is a vector graphics game system from 1983 that normally only produces black & white graphics, which is why the games came with colored display overlays. However, Youtuber Arcade Jason has put his modding skills to work, hacking an old Vectrex system to display color.
He did another video as well, showing more of the inner workings as to how he did it:
@titleknown & @highway62
















