Cutting Corners Ruler by Sharyn Craig. Turn ordinary into extraordinary with a simple ruler that works wonders! Sharyn brings her secret technique to you with this ruler and the downloadable16 page booklet of terrific instructions includes a bonus setting pattern. The Cutting Corners Ruler gives you the simple and accurate measurements to cut off a corner from a block, a square, a rectangle, or triangle, while leaving the seam allowance on the remaining piece. The ruler has markings from 1/2" corner cut to 5" corner cut.