I built this gizmo based on one of the contraptions I found on this great site. It’s by a preschool teacher who makes great sensory tables for his class. This a smaller version for the guys and this is one of those things that just guarantee squeals of delight for hours. Something about this age, they love to feed things into openings and see them come out at the other end. Most of their favorite exhibits at the Indianapolis Children’s Museum exemplify this concept.
Here is the contraption in action with just the rectangular chutes.
To make it, I chose a medium size box to be a base and just coincidentally had two long rectangular boxes and a cardboard tube for the chutes. I just used a pair of scissors to cut out squares above the middle of the box and below the middle of the box and then pushed the rectangular boxes through. You will have to cut and fold the cardboard box to make the chutes fit. Cardboard is very forgiving and even more forgiving is the duct tape. You have to play around with it until it works.
Here is one side: