Great Ball Contraption

A great ball contraption, also known as a GBC or a marble run, is a machine that receives balls from one module and passes them on to another module. This module is a miniloop, meaning it doesn't pass the balls on to another module but loops the balls within itself. The module is a wheel lift, one of the most common GBC modules, which is a large rotating wheel that lifts the balls from the bottom and brings them to the top.

The wheel lift module is dressed up as a watermill with a waterwheel alongside its mill. The mill has a half-timber design and is situated on hilly land with a stream flowing around it where the balls can roll on, into the waterwheel, and back out onto the stream through an opening on the side of the mill.

Building a marble run is a timeless, simple and fun STEM project, and a watermill was one of the earliest examples of science, technology, engineering, and math, as it uses hydropower and contains many mechanical processes.

The model is made up of 999 pieces.