Back in the day, when I studied my first differential methods course, I had a notion. I’ll write my own finite element solver. FEM is a beautifully complicated methods. Nothing about it is simplistic, except the fact that in the end it is necessary to solve a linear equation system. Did I say that is simple? Of course not. Even there the system is susceptible to floating point inaccuracy, spurious solutions and what not.
It is, however, one of the most versatile, accurate and flexible methods out there. Given that you are willing to formulate the math that comes along with it. So for now, drEMe is my dream, under slow and steady development, ready to see the light of day. Unless I will be very rich, it will not be open-source, however.