1. An object orientation marker for use in a motion tracking system for tracking motion of an object to which the object orientation marker is coupled, the object orientation marker comprising: an optically transparent substrate having a front surface and a rear surface; front artwork applied to the front surface of the substrate; rear artwork applied to the rear surface of the substrate; wherein at least one of the front artwork and the rear artwork comprises one or more landmarks configured to be viewable in an image of the object orientation marker; and wherein the front artwork and the rear artwork comprise gratings configured to create moiré patterns, the moiré patterns being configured to be sensitive to changes in orientation.