I think this is from Pete Della rocca on DIY Halloween Props. If you post the picture on the FB page, he will respond. He showed some pictures on how to make it.
I can build a static prop very well but I kind of such at motors. How do I wire up a wiper motor and hook it up to make a seesaw go up and down? My plan is to make a haunted playground addition to my graveyard this year.