Great Arcs is an electromechanical projection installation involving two projection machines. The first in a a long solenoid driven pendulum. A monochrome image of a young woman's face from a painting by Ingre slides and ripples across this surface as the pendulum moves. The pendulum also gives the timing for a two frame animation displayed in a small bathroom mirror, driven by a simple solenoid arrangement installed in an old slide projector. The image is of a naked man running, in profile, from Muybridge. Timing of the animation is from the pendulum, thus the two images are in sync, one digital and one analog, as it were. It is not possible to view the two images at once, but the sound of the solenoid driving the animation is clearly audible. The work is thus replete with dualisms.