The idea of the spin dropper thing was to design a drawing machine that would paint a piece of paper with four custom-designed paintbrushes.
The paintbrushes are attached to a disc that spins on a rod. It is spun due to a weight on a long piece of string attached to a pulley system.
There are three versions of the spin dropper thing all three of the spin dropper things all had the same objective to paint a piece of paper. Each version was made with a few changes in the design.