For this apparatus, I used three boxes. The first box---the support box---was approximately the width of the table on one side. It was also both narrow and tall on its other two sides. Since it was the width of the table and fit snugly inside the table, it was easy to tape it securely into the table. The narrowness made it possible for the chutes to pass through it. The height allowed the chutes to be set on an incline. Two other boxes were used for the chutes. One of the chutes in the picture above is a box that held window blinds and the second chute is a box that held an artificial Christmas tree. I cut out both ends of the box. Without those ends, the chutes collapse easily. When they are embedded in the support box, though, they are quite stable.
Here are three boxes I used to make closed chutes three years ago.
To make the holes for the chutes, I first trace an end of the "chute" box onto the support box near what will be the top.
When the holes are cut, I insert the chutes through both holes.
When I have taped all the chutes in place, I tape the apparatus to the table. I orient it so the higher end of the chute is above the table and the lower end extends over the table and directs the material into a tub on the floor next to the table.
OK, kids, it is now yours to explore!
If you are counting, there are eight children around this table playing on several different levels afforded by the apparatus.