Turns out that monster tech companies like Apple and Samsung aren’t the only ones going to court over copyright infringement. Popular athletic wear producer Lululemon filed suit against Calvin Klein last month for copying the design for its popular “Astro Pant” yoga wear.

Apparel design is especially tough to patent. Sample cases usually concern such iconic designs as Christian Louboutin’s red shoe bottoms, which a US appeals court prevented Yves Saint Laurent from copying last week in a case that strikes us as a little ridiculous because the offending shoes were red all over, but whatever. The concept makes sense: How can one patent the shape of a dress, for example?

Lululemon has taken matters into its own hands. Legal observers consider this case significant because the company all but anticipated the coming battle and armed itself accordingly by winning three separate patents for a product that looks to us like a simple set of skin-tight pants. The company’s most effective legal weapon is the overlapping fabric design on the Astro Pant’s waistline. Calvin Klein’s thievery becomes painfully obvious when looking at the respective waists in the photo above.

OK, so why are we really interested? Read more