This was a gift for an amputee friend of mine. I built a steel peg with a crutch tip onto an extra socket of hers and then adapted an airsoft rifle's barrel to cover it up. I then did a rough 3D scan of it using Autodesk's 123D software and imported the data into Solidworks. We then modeled a gun-like housing to cover the socket and 3D printed it in 4 parts. The parts and the airsoft gun's magazine were glued together to make this novelty prosthetic gun leg.