I'd expect that to be a prefixed variable with a comment of the link: link to the post you got it from here Vec_r, Vec_st, Vec_u If you just used the raw let

I'd expect that to be a prefixed variable with a comment of the link: link to the post you got it from here Vec_r, Vec_st, Vec_u If you just used the raw letters that's jank. Single letter variables should only be used in very short code blocks or loops.