The purpose is to show that some people do not take the blessings of Christ’s atonement, but he still suffered for their sins. Why not take those blessings happily, instead of denying them. You take the ding-dongs or whatever you have and ask one person if they want that object. They will say “yes” or “no”. No matter the answer the young man who is doing the push-ups does 5 or 10. Do this for the entire class.