Some things I have been thinking about are implementing a multiple line drawing algorithm using SIMD, but it seems like it won't work too well. Another thing I have been working on is my orbital mechanics function library. Most of the functions seem too simple to put them in a library so I will probably end up just using a function where needed instead of calling it as a subroutine.
I have also been reading some of the background stories that were written about the project I inherited. They are quite interesting and I might rewrite them while adding some of my own thoughts and imagination.