Jan Schoonhoven is widely known for his extensive and systematic investigations into light, form, and volume through both his sculptural wall reliefs and works on paper. While the ZERO movement was no longer active in the second half of the 1960s, Schoonhoven persisted in making his distinctive monochromatic reliefs. From 1966 on, Schoonhoven supplemented the prototypical quadratic shape, as seen in the relief R72-5, with new motifs such as sloping inner surfaces, diagonal lines and star shapes, of which the large wall relief shows a beautiful example.