Perfect in all points. We say of a pun or riddle, “It does not go on all fours,” it will not hold good in every way. Lord Macaulay says, “It is not easy to make a simile go on all fours.” Sir Edward Coke says, “Nullum simile quatuor pedibus currit. ” The metaphor is taken from a horse, which is lame if only one of its legs is injured. All four must be sound in order that it may go.