Step-by-step tutorial
Step 1
My daughter began by decorating the tubes with strips of colorful tape. When she was done, I cut the rolls lengthwise and then she decorated the inside of the rolls with markers.
Final result!
With her help and input, I taped the tubes to a canvas with blue painters tape, and then we tested the run to see if it worked. It did! If you look closely you'll see an orange marble falling (very quickly) out of the bottom of the last chute. The nice thing about the tape is that you can move the parts around easily, add new chutes, and test out different configurations. After this prototype, we made another much larger run directly on our newly-painted walls--and it worked out great. Happy rolling!