This year, we're going to have some kicking legs under a hay bale. We want another hay bale dangling from a rope through a pulley, moving up and down like it's going to fall. I can't find any plans or tutorials for this sort of thing, so I was hoping someone could help me. We know that the "hay bale" in the air will need to be very light, probably cardboard or the like covered in hay, but beyond that I just don't know what to do. We're familiar with pneumatics, wiper motors, and rotisserie motors, so if anyone has any great ideas using one of those we'd be most appreciative.