Constellations of thought rotate around like the cover of Led Zeppelin III or the wheel of a rotary telephone, an object common to domestic space during the era of my childhood, replaced over time by cellphones. Thinking of the Led Zeppelin album, I kneel beside my unalphabetized, unsystematized wall of vinyl whispering, “Come out, come out, wherever you are!”
There it is, a psychedelic thing of beauty. “Visual Creations by Zacron,” reads the circular stamp beside the credits on the inner sleeve. I guess this device I’m imagining is a volvelle, a wheel chart featuring concentric circles with pointers. Volvelles were used in medieval Europe to calculate the phases of the sun and moon. “While at the Royal Academy Schools,” I learn, “Zacron produced a rotating book” called One Line and a Box.
Users could ask the book “questions about their interaction with the environment,” as they might using devices like the Tarot or the I Ching. From this earlier work, Zacron derived the idea for the design of Led Zeppelin III. My courses begin to shape up into elaborate nested allegories.