I just got my six Universe Micromaster trains in the mail from KBToys.com. The other six-combiner's parts combine into that ship/sled thing. What do the trains parts do? I see that the trains are able to tow the feet (there's a peg or hole on the underside of the heels). The gun can plug into the hole in the top-front side of the foot, and the fists can plug onto the gun. But I can't find any intentional-looking thing to do with the hips and chest. Any ideas?