Kewel, Annabelle!!... that's very clever! I bet you could use that little diamond LOADS of different ways. A lot of times, I save the rubbah scraps, but haven't done much with it. This sounds interesting!
Let me share with you how I do my Print Pattern. I first saw this done on an awesome BRAK that was sent to me by CKarasz (Cindy). You ink up the P/P.... then, with a darker color marker (held at about a 45degree angle), just run the marker down the sides of the diamonds. I usually 'HUFF' the stamp before stamping it on my c/s... that re-moistens the ink. Also.... it's a really neat look to just run the marker down one side of the diamond.... VERY neat '3D' look. I love the look of this SO much, I hardly ever use P/P without doing it this way. Really adds dimension to the finished piece.
Happy Stamping....