What is the meaning of xx / yy?

[WesleyAC]

I'm looking at the docs for Matter.Composites.stack. Most of the params are pretty intuitive, but I can't figure out what xx and yy mean? Are these documented?

[WesleyAC]

Ah, I looked at the code and figured it out — it's the X/Y position of the start of the stack. It'd be great if the docs explained that :)