The artist rearranged the planned original installation and the work has since been shown in different configurations. Until the mid-1960s Bell concentrated on making works using a box format. In 1968 he said that what interested him most about his later boxes all seemed to happen in certain sections of the unit. By then he felt that this format had become an inhibiting factor which he had to destroy or pass beyond. He began to experiment with works of an environmental character and to create a space which people could walk around and into, and at the same time see through. However, in the interests of safety visitors must keep behind the barriers.
Inspired by a true story, Invincible recounts the last 48 hours in the life of Marc-Antoine Bernier, a 14-year-old boy on a desperate quest for freedom.