I must have missed them. Looks like a lot of compound curves. I'm told that TinkerCAD is a surface modeling program and is limited in the kinds of shapes it is capable of. So far, all the models I have made have been low in their compounds but still a challenge. I'm not saying "not possible" but challenging--especially the ends. The main body is a basic extrusion but the end caps are going to require some fancy dancing.
Do you have access to drawings? I saw several full color patterns (looked like paper models) in a Google image search, I wonder if those would help.
