I always thought it's the same reason as when doing math on paper starting in elementary school you'd call things x, y, z, h, w, w2... etc. instead of triangle_

I always thought it's the same reason as when doing math on paper starting in elementary school you'd call things x, y, z, h, w, w2... etc. instead of triangle_width... etc. In math'ish problems naming/algorithm (noise ratio) needs to be kept low, otherwise you can't read through it. You want to elevate symbols between type/vars in reader's attention (what's happening) as opposed to being detailed in naming (which is less of a problem to recall). It's the same in other languages, just look at SHA calculation in C or anything else - it's the same, math'ish style (and it's good). ps. another answer may be that writing code this way uses less ink! :)