I really thought that using the greek letter for pi (or theta, etc) was something you do to show your programming language supports unicode identifiers but that

I really thought that using the greek letter for pi (or theta, etc) was something you do to show your programming language supports unicode identifiers but that nobody actually does in real life. I wonder how people input this, do they know the Alt+xyz combo, do they select-copy-paste or is there another way that to write these characters that I'm not aware of? Just to be clear, I don't mean people who are actually using Greek language for input - it's pretty obvious how they would type that character :)