Did anyone see Sewing With Nancy yesterday?
She demonstrated piped binding.
She added the piping first, but about an inch before she got to the corner, she pinned the piping, then clipped it right at the corner, stopping just sort of the stitching that holds the piping in it's fabric covering. Then it made a right angle when it turned the corner.
Gosh, I hope that makes sense. In my head the pictures are perfect!