 The Nelson @-@ Atkins Museum of Art 's Olive Orchard ( F715 ) was expressed by Van Gogh in a letter of July 1889 as an orchard of olive trees with gray leaves , " their violet shadows lying on the sunny sand . " By contrast , the shadows accentuate the heat of the Provençal sun . The " repetitive , rectangular brush strokes " convey an energy that heightens the emotional impact of this work . 
