The last part of my RPN Scientific Calculator is the keypad. Before, I had considered trying to make individual key labels somehow. If I could print them on something like the material credit cards are made out of, I could cut them up and glue them to the keys. In the end, gluing on 42 labels without getting glue inside any of the buttons sounded daunting. Instead, I was able to make one out of stamp rubber on the laser cutter at our hackerspace. It turned out really well and I was able to paint the buttons different colors. At this point, there is nothing left to add, so I consider the project totally finished.