Source: https://www.artsy.net/artwork/dennis-oppenheim-2-dimensional-information-contour-lines-transferred-from-point-a-to-location-b-lines-scribed-on-swamp-grid-with-sickle-mower-cuts-filled-with-aluminum-filings-residue-from-aluminum-borings-piece-completely-submerged-in-water-at-high-tide-12-00-noon-size-175-x-200-photo-infrared