I’ve been dabbling in this, and created my own keyboard layout to include all kinds of math characters using the right Alt key for level 3 and level 4 shift. Also replaced caps lock with the compose key. Didn’t take too long to get accustomed to it since it’s a corruption of the Greek keyboard layout (which is laid out similar to QWERTY).

I haven’t had the audacity to use it in production code, but it’s interesting to play around with and great for quick note taking or hacker news comments. (Sadly I’m on my phone right now to not make use of it for this comment)