In this activity, learners make a Benham Top to explore visual illusions and optics. This activity guide includes three different instructions for making the spinner using various recycled materials (old CD, margarine container top, cardboard). The site includes disk graphics (large and small) as well as a blank disk for learners to make their own patterns. The site also explains theories about how the Benham's Disk, with a pattern of black and white marks, can cause people to see colors. Note: supply requirements will depend on the type of Benham's disk you want to build; not all supplies listed are required.