The other issue is whether the pumpkin has a smooth surface or whether it has a "grooved" surface. Grooved lines on R2-D2 obviously wouldn't work. Finally, for R2-D2, because I didn't have a pattern, I needed to have pictures of anatomically accurate R2-D2 pictures. I found these both with the Weta Sideshow R2-D2 sculpture and with some videos of fully functional R2-D2 units from the R2-D2 Maker's group. Then its a matter of taking the "real" R2-D2 and transposing it to the pumpkin you have.