Corner Pop a tool and technique that will give you high success adding fabric corners to basic shapes. For years we’ve been layering small squares on big squares, marking & stitching on a diagonal line, then hoping everything lines up when we fold the small corner section back into place. If you’ve tried it, you know the pitfalls: too big, too short, too crooked and way too wasteful. No more. With your new Corner Pop tool, you will be able to trim rather than mark, add an oversized replacement triangle and then square everything to a perfect size.