An Abstract Drawing One day in a drawing class, the teacher told the class to draw an abstract(抽象的) drawing. After a while, a small boy turned his drawing in . The teacher look at it but saw nothing , only a piece of white paper. "What did you draw?" said the teacher. "A cow eats grass," the boy answered. "Where is the grass?" "The cow has eaten it up," replied the boy. "Well, but where is the cow?" the teacher asked again. "It ate up the grass and then went away to drink water."