Thus ought recreation sometimes to be given to the mind, that it may return to you better fitted for thought

From The Comedies of Terence and The Fables of Phaedrus translated by Henry Thomas Riley. Fable XIV, ÆSOP AT PLAY.

An Athenian seeing Æsop in a crowd of boys at play with nuts, stopped and laughed at him for a madman. As soon as the Sage,—a laugher at others rather than one to be laughed at,—perceived this, he placed an unstrung bow in the middle of the road: “Hark you, wise man,” said he, “unriddle what I have done.” The people gather round. The man torments his invention a long time, but cannot make out the reason of the proposed question. At last he gives up. Upon this, the victorious Philosopher says: “You will soon break the bow, if you always keep it bent; but if you loosen it, it will be fit for use when you want it.”

Thus ought recreation sometimes to be given to the mind, that it may return to you better fitted for thought.