An instance of the emblematic character of early riddles is seen in that proposed by the Sphinx to OEdipus. "What is that which goes on four legs in the morning, on two in the middle of the day, and on three in the evening?" And in the riddle of Cleobulus, one of the seven wise men: "There was a father, and he had twelve daughters; each of his daughters had thirty children; some were white and others black, and though immortal they all taste of death." Also in the following griphi, which are capable of receiving more than one answer. The first two are respectively by Eubulus and Alexis--writers of the "New Comedy"--who flourished in the first half of the 4th century, B.C. "I know a thing, which while it's young is heavy, But when it's old, though void of wings, can fly, With lightest motion out of sight of earth. "It is not mortal or immortal either But as it were compounded of the two, So that it neither lives the life of man Nor yet of god, but is incessantly New born again, and then again Of this its present life invisible, Yet it is known and recognised by all." From Hermippus:-- "There are two sisters, one of whom brings forth, The other and in turn becomes her daughter." Diphilus, in his Theseus, says, there were once three Samian damsels, who on the day of the festival of Adonis delighted themselves with riddles. One of them proposed, "What is the strongest of all things?" Another answered, "Iron, because it is that with which men dig and cut." The third said, "The blacksmith, for he bends and fashions the iron." But the first replied, "Love, for it can subdue the blacksmith himself." The following is from Theadectes, a pupil of Isocrates, who lived about 300 B.C., and wrote fifty tragedies--none of which survive. "Nothing which earth or sea produces, Nought among mortals hath so great increase. In its first birth the largest it appears, Small in its prime, and in old age again, In form and size it far surpasses all."[17] To make a riddle, that is a real test of ingenuity for all, and which but one answer satisfies, shows an advanced stage of the art. The ancient riddles were almost invariably symbolical, and either too vague or too learned. They seem to us not to have sufficient point to be humorous, but no doubt they were thought so in their day.