For this dog toy, it was initially just a single wind-up toy.  However, after being inspired by all of the recent snow, it occurred to me that this toy could be expanded to a dog sled set-up.  There will be multiple dogs that can be hooked up to a sled that has some weight on it.  The more weight that are on the sled, the more dogs that would be needed to pull the sled.  The concept of coordination could also be incorporated into this idea.  The dogs should also be huskies (if only I could draw a good one).