Undocumented particle functions

I am working on a tutorial that goes and explains how the expressions are used with examples. I will explain all the symbols, operators and arguments. And I have this weird idea if there are undocumented “particle symbols” like color, speed and position. I try “rot” like “pos”, doesn’t work.

But it seems “rotation” and “spin” are two undocumented parameters that we can manipulate with functions.

Now I will have to do some more tests, but this will create some more flexibility for animations…