In the late 1940s, Bill first began rotating canvases to this diamond shape, calling them “Spitze Bilder” (pointed pictures). He simultaneously began to produce paintings in series that are dedicated to the study of color movements on the basis of elementary geometric shapes. Due to its arrangement of colors, Verdichtung zu caput mortuum, possesses a balanced weighting of this format; the tonality seems to stabilize the colors grouped around the inner rectangle, which means that the picture does not threaten to tilt, rise or fall off in any direction. Piet Mondrian, whom Bill met in 1932, conceived the rhomboid around 1926-31. The Variationen can be understood as a kind of visual lesson for the viewer on the production and construction of artworks. The 15 lithographs illustrate the conversion of an equilateral triangle into an equilateral octagon as it develops outwards in a spiral. The prints represent his first systematic series.