What is this passage from Shakespeare King Lear saying?

What is this passage from Shakespeare King Lear saying?

• Fool If a man's brains were in's heels, were't not in danger of kibes? KING LEAR Ay, boy. Fool Then, I prithee, be merry; thy wit shall ne'er go slip-shod. KING LEAR Ha, ha, ha! Fool Shalt see thy other daughter will use thee kindly; for though she's as like this as a crab's like an apple, yet I can tell what I can tell. KING LEAR Why, what canst thou tell, my boy? Fool She will taste as like this as a crab does to a crab. Thou canst tell why one's nose stands i' the middle on's face? KING LEAR No. Fool Why, to keep one's eyes of either side's nose; that what a man cannot smell out, he may spy into. KING LEAR I did her wrong-- Fool Canst tell how an oyster makes his shell? KING LEAR No. Fool Nor I neither; but I can tell why a snail has a house. KING LEAR Why? Fool Why, to put his head in; not to give it away to his daughters, and leave his horns without a case. KING LEAR I will forget my nature. So kind a father! Be my horses ready? Fool Thy asses are gone about 'em. The reason why the seven stars are no more than seven is a pretty reason. KING LEAR Because they are not eight? Fool Yes, indeed: thou wouldst make a good fool. KING LEAR To take 't again perforce! Monster ingratitude! Fool If thou wert my fool, nuncle, I'ld have thee beaten for being old before thy time. KING LEAR How's that? Fool Thou shouldst not have been old till thou hadst been wise. KING LEAR O, let me not be mad, not mad, sweet heaven Keep me in temper: I would not be mad!

• Answer:

  The fool is a "wise fool," who sees more clearly than King Lear despite being so much lower than him on the social scale. The Fool is making jokes and posing riddles, theoretically to amuse the king (his job) as the king is in distress. But actually, most of what he says really twists the knife, saying that King Lear is more of a fool than he is for screwing up his life so badly. He keeps saying the king's a fool and that being so old he should be wise (but isn't) and refers obliquely to the king having messed up in his choice of which daughters to trust, and in giving away his power. He says, for example, that a snail has a house and King Lear doesn't, because he gave it away, and that the "other daughter" (Regan) that he's counting on to be nice to him probably won't be. Though she looks good, she's actually a crab underneath--which the fool can see, and mocks the king for not realizing.