Okay, so where is it explained which three concepts are being diagrammed here? Did the artist have some in mind when assigning colours, or should we use our imagination? Sadly, the linked description page at www.cai.cam.ac.uk is a 404 already.

This is also interesting as a secular, scientific monument that happens to resemble some quite traditional representations of the Christian Holy Trinity, Father, Son and Holy Spirit. Perhaps it is not an accident that "three rings" were chosen for this prominent homage.