That looks familiar. It's very similar to the pattern for the parts of team 192's bumpers from '13 and '14. We had reversible bumpers with sewn mitered corners. In '14 the cloth was a single loop that fit snuggly over the bumper wood and foam.
Here are some pictures of the making of a example corner of the bumper fabric, as well as a close up corner of '14 bumpers and '13 and '14 bumpers on their respective robots. (Might want to start from the bottom photo)
http://imgur.com/a/Z3mjy