a simple game maths library: you'll find basic modules for 2D, 3D, 4D, homogeneous vectors, as well as matrices. And a couple of other things.
I had further plans for this library, but I couldn't find the better way to implement them yet. For people looking for a well maintained solution, I suggest having a look at https://github.com/dbuenzli/gg instead, which offer a somewhat similar but richer interface.
the library code (in the src directory) is provided under LGPLv3 (see LICENCE.LGPLv3), and the test code (in the test directory) under GPLv3 (see LICENCE.GPLv3).