Hans Hinterreiter (1902-1989) was a Swiss painter who developed a formal geometric theory of ‵‵Concrete Art′′. He specified notations for his constructions and his colors that allow a concise characterization of any of his artworks. Considerable mathematical thought went into the design of his system, particularly his development of nonlinear geometric deformations that flowingly fill rectangles and circles. This paper explains some mathematical aspects of his methods and illustrates software I wrote to allow his designs to be reconstructed from his symbolic descriptions. Hinterreiter achieved an astounding synthesis of artistry and mathematical rigor that led to museum-worthy results. He deserves to be better known as a model of systematic artistic practice.