This is an awesome team building lesson. You need to purchase the materials. I bought mine at our local Dollar Tree. The tray is a butter dish! Student directions provided and a video sample. This Design Thinking Collaboration Challenge forces the students to really work together. The solution provided is not the only option. The students can come up with great ideas, but make sure you hold them accountable for the time. They must be able to slow that marble down to at least 2 seconds! . The lesson takes one 60 min block. Have fun.