Skechers became the number-two footwear brand in 2015, but they might owe a lot of that to brands like adidas and Nike. The recent infringement lawsuit against the top mom brand isn't just a fluke, and several companies have filed against for infringement. Skechers has quite a history of borrowing designs. Regardless, they've turned their derivative styles into a multi-billion-dollar business. We've analyzed 10 of these models, and graded their execution based on how close they came to the original design.