Rube Goldberg machine of the day

https://www.youtube.com/watch?v=yhOhSYCnpj0&feature=youtu.be

As relaxing, amusing and intriguing as any other: "an impressive Rube Goldberg machine with a 4-minute course. The beads move in a chain reaction divided into several more complex steps, including the one with a whiteboard that turns to release new balls positioned on the back side."