One very early pseudo-3D game (perhaps the first?) was Sega's Fonz, which drew a not-really-perspective-corrected road using discrete logic. AFAIK it hasn't even been emulated by MAME yet.
This website again... every time I see it, I get an irresistible urge to write my own old-school racing game in Javascript (it's been done, I know, but not by me).
I'd better get away from it before I "forget" that I have deadlines to stick to.
Nintendo still has to do that to some extent in order to get competitive performance on outdated hardware. They even managed to get Smash 4 running at 1080p60fps on the Wii U.
For me, the math is always easier when I'm writing something myself, than when I'm reading about how someone else did it. Rather than just a description of something that someone else tells you works, you've got lists of approaches that you came up with, your own opinions of positives and negatives of each, and an intuitive grasp of why you do something a specific way.
Work your way into a problem until you don't know the answer to something. Then keep experimenting with half-ideas and hunches. If you're still stuck, read some about how someone else did it; the math will be easier to tie into your own experiences, and you'll get more out of it.
Oh yeah, and shameless plug for my 6502 IDE which draws a pseudo-3D road on the Atari 2600 :) http://8bitworkshop.com/?platform=vcs&file=examples%2Froad