I worked on the Unity Sketch Challenge for their release party (see here http://triplethescraps.blogspot.com/...y-sketch.html). I struggled and struggled with the scallops on the edge and then the postage idea came to me. There is a stamp image on the postcard and the ribbon slide has the same scallops on its edge. No Unity stamps :( (yet)!
Sorry for any boo-boos or typos in the description as I am trying to make the deadline! Thanks for looking!