It was also depicted in a woodcut by the German artist Heinz Kiwitz and by Rene Magritte in the painting Le Drapeau Noir .
Heinz Kiwitz was later killed fighting in the International Brigades .
It was also depicted in a woodcut by the German artist Heinz Kiwitz , who was later killed fighting in the International Brigades , and by Rene Magritte in the painting Le Drapeau Noir .