Action represents the formation of Turrell's "Space Construction" series. In these, Turrell had rooms specially designed into two parts, the viewing area and the sensing area. The viewing area is where the observer of the work would stand. The sensing area is the area beyond a partition that appears to be a solid wall, though there is an aperture in it. Because of specially designed, diffused lighting in the sensing area, the partition appears to be solid. If viewed long enough, the illusion dissipates, and the viewer can take action, reaching into the sensing area.