An analogy compares of two otherwise dissimilar things based on a similarity in some particular aspect. Because one aspect of the thing resembles that in the other thing,  there is an inference that other aspects are also similar. An analogy is useful in explaining  a concept or process that the audience may not be familiar.
An analogy normally is more complex than a metaphor or simile. How do you craft an analogy? First, figure out what your audience—jury—is familiar with and then look for characteristics in that item that could be like your thing. A well-crafted analogy often begins with a metaphor or simile.
Gerry Spence in Silkwood v. Kerr-McGee: “Well, we talked about “strict liability” at the outset, and you’ll hear the court tell you about ‘strict liability,’ and it simply means: ‘If the lion got away, Kerr-McGee has to pay.’ It’s that simple – that’s the law.
“You remember what I told you in the opening statement about strict liability? It came out of the Old English common law. Some guy brought an old lion on his ground, and he put it in a cage – and lions are dangerous – and through no negligence of his own – through no fault of his own, the lion got away. Nobody knew how – like in this case, ‘nobody knew how.’
“And, the lion went out and he ate up some people – and they sued the man. And they said, you know: ‘Pay. It was your lion, and he got away.’ And, the man says: ‘But I did everything in my power – I had a good cage – had a good lock on the door – I did everything that I could – I had security – I had trained people watching the lion – and it isn’t my fault that he got away.’ Why should you punish him? They said: ‘We have to punish him – we have to punish you – you have to pay’” You have to pay because it was your lion – unless the person who was hurt let the lion out himself. That’s the only defense in this case: unless in this case Karen Silkwood was the one who intentionally took the plutonium out, and ‘let the lion out,’ that is the only defense, and that is why we have heard so much about it.”
Martin Luther King, Jr. in his “I have a dream” speech: “In a sense we’ve come to our nation’s capital to cash a check. When the architects of our Republic wrote the magnificent words of the Constitution and the Declaration of Independence, they were signing a promissory note to which every American was to fall heir. This note was a promise that all men-yes, black men as well as white men-would he given the inalienable rights of life, liberty the pursuit of happiness. It is obvious today that America has defaulted on that promissory note. Instead of honoring this sacred obligation, America has given the Negro people a bad check, a check which has come back marked ‘insufficient funds.’”
Gerry Spence, as defense counsel in the mock trial of Lee Harvey Oswald: Watch the old man and a bird analogy. 


Vincent Bugliosi in his book about the O. J. Simpson case, entitled Outrage: The Five Reasons Why O. J. Simpson Got Away with Murder provides this argument that he would have made in the case: “I wonder if any of you folks have read Victor Hugo’s account of the octopus. He tells us of how it doesn’t have any beak to defend itself like a bird, no claws like a lion, nor teeth like an alligator. But it does have what could be called an ink bag, and to protect itself when it is attacked it lets out a dark fluid from this bag, thus making all of the surrounding water dark and murky, enabling the octopus to escape into the darkness.

“Now I ask you folks, is there any similarity between that description of the ink bag of the octopus and the defense in this case? Has the defense shown you any real, valid, legitimate defense reasonably based on the evidence, or has it sought to employ the ink bag of the octopus, and by making everything dark around Mr. Simpson, tried to let him escape into the darkness.

“I intend to clear up the water which defense counsel have sought to muddy, so that you folks can clearly see the evidence, the facts, the issues in this case, so that you can behold the form of the retreating octopus and bring this defendant back to face justice.”
CAVEAT
Although analogies can be persuasive, they are also vulnerable to attack. They are susceptible to attack because an aspect of one thing is compared to a similar aspect of another thing that is otherwise different. Often, the analogy can be turned back against the lawyer who offered it.
Vincent Bugliosi in Outrage countered the defense’s analogy with one that  he would have made in the case: “I think that counsels’ problem is that they misconceive what circumstantial evidence is all about. Circumstantial evidence is not, as they claim, like a chain. You could have a chain spanning the Atlantic Ocean from Nova Scotia to Bordeaux, France, consisting of millions of links, and with one weak link that chain is broken.

“Circumstantial evidence to the contrary, is like a rope. And each fact is a strand of that rope. And as the prosecution piles one fact upon another we add strands and we add strength to that rope. If one strand breaks – and I’m not conceding for one moment that any strand has broken in this case – but if one strand does break, the rope is not broken. The strength of the rope is barely diminished. Why? Because there are so many other strands of almost steel-like strength that the rope is still more than strong enough to bind these two defendants to justice. That’s what circumstantial evidence is all about.”
Microsoft monopoly case: Defendant Microsoft’s final witness was Richard Schmalensee, a Massachusetts Institute of Technology professor, was Microsoft’s final witness, and he argued that the extreme popularity of Microsoft’s Windows operating system does not mean that other companies cannot develop competing systems. The expert argued, “That’s like saying I have a grocery store and you don’t – and that makes it hard to compete with me in groceries.”
Judge had trouble with the analogy and turned it against the expert, stating: “I have trouble with your grocery-store analogy. While your competitor is building his little neighborhood store, you are building a supermarket and your competitor has fewer and fewer customers because they are looking for products in your megamarket and your competition is always trying to play catch-up.”