In 2023, Sullivan developed two images at Flatbed to become polymer gravure etchings. First was the image of “Box” 1, a hand-drawn skeletal probing of the space of a simple box. He had drawn this image with a certain hand-carved reed dipped a sepia-toned ink. The second was Popular Mechanics 8 + 3, a diptych intaglio image based on Sullivan's landscape drawings which are on sheets from a Popular Mechanics magazine printed with the raised-dot patterns of Braille. The images though starkly different from each other, share Sullivan’s search for the unseen.