The rhythmograms of Heinrich Heidersberger (1906-2006) are intricately curved compositions of pure light that weave together abstract figures, organisms and space. The artist created these complex light patterns during the 1950s and 1960s, capturing the invisible and elusive worlds of time and motion in a single frame. Outfitted not with a camera, but rather with an ingenious, room-sized, deconstructed photographic machine of his own design, Heidersberger traced the geometry of delicate waves and oscillations: his machine could reproduce the elegant orbit of even a single ray of light onto a photographic plate. Widely known as an architectural photographer of postwar modernism, Heidersberger's little-known rhythmograms serve as a fascinating bridge between the work of early modernists and the future of algorithmic art and architecture. This is the first critical study of these rhythmograms in all their delicate detail.