Algodoo

I was going to build it with my epic negative-length spring engine, but it didn't work, so I tried a negative-damping spring engine, but it also did not work, so I ended up using a spawn rocket I made a while ago.

I really wanted to use an attraction engine here, but the rules prevent that. A spawn engine that produces a toque would also work, but I already had the rocket handy.

I needed an engine with good starting torque, but spring engines are not good for that. And I didn't want to bother with making a spawn engine for that purpose.