They're at it again. Apple and Samsung, two titans of mobile technology, are resolving in a San Jose federal courtroom the issues they can't in the marketplace — for a second time.

Apple says Samsung infringed on its patents, effectively stealing the key elements of the iPhone for a whole range of subsequent Samsung smartphones, each of which Apple is seeking to remove from the market (and to get punitive damages for). Samsung has purchased a few software patents of its own, and is wielding those against Apple's iOS in a kind of rear-guard action.

Not a great deal has happened yet in the trial, which started — appropriately enough, some might say — on April Fools' Day. The only noteworthy incident, so far, was the curious sight of a top Apple executive denying he knew anything about Ellen's Oscar selfie, which happened to be taken on a Samsung phone.

Still, you might have a few questions about this courtroom drama, and it's worth getting up to speed on them now, albeit as briefly as possible.

1. Didn't we just see this movie?

In 2012, Apple won a very similar case against Samsung in this exact same courtroom. The jury awarded Apple $1 billion in damages, which the judge later knocked down by a mere $70 million; that case is on appeal. Samsung has not paid anything yet, despite hilarious Internet rumors that the Korean company paid Apple entirely in nickels.

2. So, why are we seeing the sequel?

The main difference in Apple v. Samsung redux is that it accuses a new generation of Samsung smartphones and phablets, such as the Galaxy Note 2 and the Galaxy Tab 2. Oh, and Samsung didn't have those patents it claims Apple is infringing last time around. In court, Apple is accusing its rival of patent shopping with malicious intent.

Other than that, both sides seem to be gearing up for almost identical arguments to the last trial. So far, Apple is sticking to what worked last time around: an emotional appeal to the necessity to protect innovation, a stirring narrative about how hard the iPhone was to develop.

Samsung's lawyers may use some more fancy footwork this time, but their basic argument hasn't changed: to punish rival smartphones at this fundamental a level — because theirs happen to have the same kinds of curves at its corners, for example — is to stifle competition. Apple's five patents at issue here are effectively invalid, Samsung says.

3. This is really a proxy battle for iOS vs. Android, right?

That depends on your point of view. Apple says no; it's just about basic patent infringement and the need to protect creative risk-taking. Samsung says yes, because the more it can frame Apple as obsessively anti-Google and anti-Android, the more Samsung looks like an innocent bystander caught in the crossfire of Silicon Valley giants.

To this end, Samsung has already pulled out of its sleeve an email in which Steve Jobs declared "holy war" against Android a priority for Apple. This is not far from the "thermonuclear war" Jobs threatened to wage on a mobile operating system he considered a blatant theft of Apple's property. Jobs' choice of words, however, may not matter compared to the impossibility of getting a jury in Silicon Valley that doesn't automatically venerate the local kid.

4. What's the endgame here?

We're looking at weeks — possibly months even — of arguments before Judge Lucy Koh, who is known for her tough manner and colorful turns of phrase. (She jokingly accused Apple lawyers of "smoking crack" Tuesday because they were overly optimistic about how fast the trial would proceed.) Then a jury will decide the winner — if there is to be any.

Apple is seeking damages of $2 billion this time around, plus banning the offending Samsung phones from sale in the U.S. That latter part didn't fly the last time around, and given how many of the phones in question have already been retired anyway, it's kind of a losing battle to begin with. Smartphone cycles are faster than the law and always will be. More likely, Apple is using this as a test case to see if it can fire a warning shot at Android smartphone manufacturers, force some design changes and claw back some iPhone market share in the interim.

Samsung, on the other hand, is asking for a mere $7 million in damages for the infringement of its patents. Or, as Tim Cook could call it, walking-around money for Apple.

5. What was that about the Apple executive and Ellen?

In court on Tuesday, Samsung attorney Bill Price questioned Phil Schiller, Apple's VP of marketing. Price was trying to grill Schiller about those patents Samsung says Apple infringed, which happen to be photo and video patents, and asked whether the iPhone could take a selfie "like Ellen DeGeneres did during the Oscars."

That selfie heard round the world was rather shamelessly associated with the Samsung phone on which it was taken. Schiller may have sensed a trap. He told the attorney he wasn't familiar with the most-retweeted tweet in history — and this came from the regularly tweeting, 122,000-follower @pschiller.

Stick with Mashable as we continue to cover the courtroom drama — both its serious threats and the lighter moments.