When it comes to smartphones, is the whole greater than the sum of its parts? Apple thinks so. But on Tuesday, in a patent suit with hundreds of millions of dollars at stake, the company’s lawyers faced off against a Samsung legal team that thinks different.

In opening arguments for a damages phase of the patent suit — Samsung already has been found to infringe — Apple attorney Bill Lee argued that three design patents, while covering merely cosmetic aspects of iPhones, are in fact key to making the phones look good and work well.

“Design is what ties it all together,” Lee said in US District Court, Northern District of California, located in the Silicon Valley city of San Jose. “The end result was revolutionary.”

But Samsung’s attorney, John Quinn, held up specific phone components — screens and displays — and told a jury that’s where the infringement took place. “This is the article of manufacture,” Quinn said of the components. “Apple is certainly not entitled to the profits on the whole phone.”

The case not only will determine how much Samsung has to pay, but also how much countless other technology companies might have to worry about patents in the future. The more broadly patents apply, the more they’re worth, the greater leverage patent holders have, and the harder it is for competitors to challenge them.

The lawsuit began in 2011 and made it all the way to the Supreme Court in late 2016 before being sent back to the lower court, where it resumed Monday. Earlier cases already found that several now-obsolete Samsung devices infringed five Apple patents — two utility patents and three design patents — but what’s still up in the air is exactly how much Samsung must pay in damages.

Samsung has already paid $548 million, but a $399 million portion of that could be reduced because of the Supreme Court decision. It centered on an issue of what exactly constitutes an “article of manufacture” that a patent governs. Apple argues that it should be the entire product — a phone in this instance — but Samsung is making the case that it could just be a component of a phone.

Samsung argues that a company that owns a patent on just a car’s cup holder shouldn’t be able to collect the profit from the entire car. Some estimates say more than 250,000 patents go into a smartphone, and the original penalty against Samsung was based on the value of the entire phone.

But Apple argues that though Samsung’s devices infringed only part of the iPhone’s design, Samsung should pay damages based on the value of its entire device. If one phone’s design is similar to that of an iPhone, the thinking goes, Apple could lose the sale of an entire phone.

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