Here's another Montessori inspired idea. I cut a slit in the lid of a coffee can for S to insert disks. He has learned to open the lid to remove the disks, but you could also cut a hole in the side for removal. For disks I used the lids that came on the free dog food from Target! I have lots more, but I need to wait until our dog has eaten the food. This activity keeps S engaged longer than most. Thanks to The Wonder Years for the idea!