Two Studies of a Shepherd Resting, Adriaen van de Velde, 1666 - 1671
Van de Velde here drew the same model twice: in one study the boy is asleep with his head resting on his right arm, and in the other awake and semi upright. The artist could use the same pair of legs for both poses, which explains why he only drew them once on the sheet of paper. Seventeenth-century artists did not like doing the same work twice.