"This collapse of separate times into one image creates another push/pull with the experience of depth. The superimpositions seem to lie on top of the image, yet they move into depth, creating what Gehr describes as a 'teasing play with planes.' But the play with space and position here involves more than tension between layers. The variations on light and shadow on the two levels cause the double-exposures to pop in and out of depth. A shadow on the first level can give the superimposition a sudden burst of solidity. Gehr calls our attention to the multiplicity of depth cues that operate in a film in addition to perspective recession. The cue of overlap creates much of the amusement of the film, as the vehicles on one level plow through the phantoms on the other. Gehr was particularly fascinated by the way depth cues provided by color (with warm colors coming forward) interact with the logic of space..." – Tom Gunning