It’s been said that imitation is the sincerest form of flattery. However, when it comes to shoe design, Nike (NKE) doesn’t seem to be taking Skechers’ alleged copying lightly.

Nike filed a patent infringement lawsuit against Skechers (SKX) in federal court on Tuesday, claiming its competitor employs a “copying strategy” at the behest of CEO Robert Greenberg. The Swoosh brand says that it filed the lawsuit to defend its design innovation and stop Skechers from “free-riding” on Nike’s significant investment in talent and resources.

The lawsuit claims that Skechers is now copying two specific Nike designs: VaporMax and Air Max 270, two of the most distinctive-looking in sneakers in Nike’s lineup, which have prominent and uniquely shaped air bubbles.

“Skechers contends it merely takes inspiration from competitor products, which it calls ‘Skecherizing,’” the lawsuit states. However, Nike alleges, “Skechers’ business strategy includes copying its competitors’ designs to gain market share.”

While the case only involves two types of shoes, Nike claims Skechers has infringed a dozen patents. Nike is taking a page out of Apple’s (AAPL) playbook by obtaining multiple patents for one product and claiming infringment of all of those patents, according to one expert. Apple has filed a number of so-called design patents related to the iPhone and engaged in years-long litigation claiming Samsung infringed those patents.

“Nike is able to go through and obtain patents on each of these aspects of the design. So when they sue Skechers, they could say for each of these shoes here are six different patents we think you infringed. Each one of which potentially gets this own separate damages award,” says Christopher J. Buccafusco, a professor specializing in intellectual property law at Cardozo Law School.

But Nike might face an uphill battle with its lawsuit because intellectual property protection for design patents like the ones for its sneakers tend not to be very broad, according Buccafusco.

“You’ve got to be pretty darn similar to the plaintiff’s patent in order to infringe it,” he said. “The standard that courts will apply is the two designs are not similar; it’s that they’re substantially the same. They don’t have to be identical, but they’ve got to be pretty close to identical to infringe.”

The allegations that Skechers is knocking off its competitors are not new. Back in 2016, as mentioned by Nike in the complaint, Sneaker News put out a post titled “The Most Blatant Skechers Knock-Offs.” The article cites several examples of Skechers shoes that resembled those of competitors like Adidas (ADDYY) and Cole Haan.