IN 1966 JAMES TURRELL leased the former Mendota Hotel at the corner of Main and Hill Streets in the Ocean Park section of Santa Monica, and built a studio from the outside in: he sealed off the two main spaces from all external light by painting the windowpanes and began to work with projecting light onto the walls. This Mendota period (1966 to 1974) birthed a number of Turrell's approaches to light that relate to his consideration of the studio's walls as akin to the walls of Plato's Cave, in which prisoners believe the shadows they see on the cave wall are real because they cannot turn around and understand that what they perceive as reality is actually an illusion.