I have a cousin who shares the exact same set of grandparents I do. We're cousins on both sides of the family. Her mom and my dad are siblings, and so are her dad and my mom. (Still with me?)
In pictures from our childhood, we look uncannily similar. We're as close to being sisters as two people can possibly be without actually sharing a parent.
We had real honest-to-goodness Chicago-style pizza today. It's the double cousin of New York-style pizza.
Imagine quiche and pie as siblings and spaghetti and lasagna as siblings. Spaghetti and pie get together and have a baby: New York Pizza. Quiche and lasagna get together and have a baby, too: Chicago Pizza.
New York Pizza and Chicago Pizza aren't identical, but they're very similar. You'd almost think they share at least one parent, but they don't.
New York Pizza is way cooler and more attractive, and even more delicious. Chicago Pizza is tasty, but nothing at all like her cousin.
Chicago Pizza is good, but when I want real pizza, I'll go to New York.