Machinery is a dead simple game engine toolkit written in Go.
It started as a small piece of my fun gamedev project.
It provides definitions of vectors, polygons and rigid bodies as well as utilities around it like operations on vectors and polygons, collision detection and resolution based on SAT (Separating Axis Theory), concept of physical world linking it all together or number randomisation.
Due to it's modular nature it's simple to combine it with any rendering framework and create your own game or simulation.
I would recommend a fork or the good old copy-paste method into your own game project.