Eadweard Muybridge (UK, 1830 - 1904)

Movement of the Hand Beating Time, Plate 535 from Animal Locomotion 1884-86 Collotype - MoMA

Bernard le Bovier de Fontenelle. Frontispiece for Conversations on the Plurality of Worlds. 1686.  

A theory is exactly like a box of tools. It has nothing to do with the signifier. It must be useful. It must function. And not for itself. If no one uses it, beginning with the theoretician himself (who then ceases to be a theoretician), then the theory is worthless or the moment is inappropriate. We don't revise a theory, but construct new ones; we have no choice but to make others.

Gilles Deleuze, “'Intellectuals and power': A conversation between Michel Foucault  and  Gilles  Deleuze”

Alexander (Hammid) Hackenschmied, Rita, in Double Vision, 1942