Finger Puppet and Fridge Magnet.
Sigmund Freud originated (and named) the practice of "psychoanalysis" and remains one of the most important thinkers of the 20th century. His work has influenced literature and art, the sciences, and, of course, psychiatry. He developed a three-part model of the psyche (id, ego, and superego), studied the workings of the unconscious, and brought attention to childhood trauma as the root of adult afflictions. Freud advocated for the humane treatment of people with psychiatric disorders.