Sigmund Freud held a certain delight for machines. His first model of the system Conscious/Unconscious (Cs/UnCs), in Project for a Scientific Psychology (1895), ran on the energies of affect. Freud, in fact, called it a ‘machine.’But the problem was it kept breaking down, so he switched gears by the time of The Interpretation of Dreams (1900). Two and a half decades later, Freud offered up one of his most well-known machines through the example of the “mystic writing pad”(1925). The writing pad’s three layers operated through the cycling of traces: the traces of sense-impressions on the receptive surfaces of Perception-Consciousness (Pcpt.-Cs.) as a relatively flimsy middle layer; the UnCs as the dark resin of the bottom layer that retained impressions (as memory traces) while also “extending feelers” out toward the external world; the top protective sheet that, when lifted along with the middle layer, removed old traces so that new ones could then be deposited. It’s just a simple kids’ toy [you might know it as ‘the magic slate’] but it offered a wonderful heuristic machine for grasping the fundamentals of the psychoanalytic apparatus.