> I don't think I've ever seen a graphical system of any kind that didn't have 0,0 at the top-left corner of the monitor or viewport either, with positive x goi

> I don't think I've ever seen a graphical system of any kind that didn't have 0,0 at the top-left corner of the monitor or viewport either, with positive x going right and positive y going down. Is that because the electron beam in cathode ray tubes scanned from top left to bottom right?