Each of the three two-record sets carried the same cover art, a Theodore de Bry etching of an instrument Smith referred to as the "Celestial Monochord," taken from a mystical treatise by scientist/alchemist Robert Fludd. This etching was printed over against a different color background for each volume of the set: blue, red and green. Smith had incorporated both the music and the art into his own unusual cosmology, and each of these colors was considered by Smith to correspond to an alchemical classical element: Water, Fire, and Air, respectively. The fourth 'Labour' volume (released later by Revenant) is colored yellow to represent the element earth.