It's a genius idea to keep patients occupied — after all, it's pretty difficult to read a book or scroll through Twitter while you're in the dentist's chair (unless you're willing to play Twister with your dentist's arms). Of course, if you happen to go to the dentist fairly often, you'd probably get tired of playing the same game of Where's Waldo over and over again, but it's still better than staring at an empty wall.