I have something totally weird happening! The four-wheeled robots each have a wheel that extends off to infinity! There are these giant cylinders rolling around the place.

The tank has a few wheels like this, but it also has something that sticks up in the air and appears to go off into space.

I had a VERY quick look at the code, but I can't see why this should be happening.

Just one other (minor) suggestion - maybe you could create a new project rather than overwriting an existing one. Perhaps that has something to do with it?

Trevor

P.S. I've added the image to this posting so that everyone can see what is going on. Maybe there will be some other people who can put their finger on the problem.
Tank with artefacts