VAN GOGH SPINS A YARN

Van Gogh, Self Portrait Autumn, 1887

"In [Van Gogh's] studio, he kept a lacquered box containing balls of brightly colored yarn  that he endlessly twined and untwined to test the interaction of colors - exactly the procedure described by Chevereul, who had developed his theory as director of dyes for the royal looms at Gobelins."  [Van Gogh: The Life, Steven Naifen and Gregory White]