In making the mounts for the motors, there's been a few tricky spots to drill holes for. One of the first projects I wanted to try was to make a corner drill. You know... one that can drill around corners.
I didn't realise that under Mach3, an M0 program stop wasn't "terminate", but "pause", and that pressing Run (Alt-R) again would continue on from the next line.
High on the list for the next project is that emergency stop button I should have...