The discs are stacked on top of each other; the red below, then the blue and finally the green on top. By fixing them in the middle on a shaft or pin, the discs can be rotated independently of each other and you can seek for any possible connection. See also the conversation with Hein Reitsma at the tab: Alienation for an example.
You can print the discs yourself, cut them out and place them on top of each other with, for example, a cotter pin. You can find the file at ‘Downloads and contact’.