If you thought hipsters knew any limits, guess again: The crowd in hipster Williamsburg has granted a beachhead to a pizza invasion out of Detroit.

Emmy Squared, on Grand Street, serves the rectangular pies — with sauce atop the cheese, and no outer rim of crust.

What a diss to Ray’s Original, Famous Original Ray’s and the city’s other classic slice-venders. Even aficionados of those Chicago quiches — “deep-dish pizza” — must be appalled.

For the record: Real pizza is round and flat, with melted mozzarella atop the sauce.

“No, Detroit pizza isn’t topped with bullets,” blubber its fans to Big Apple traditionalists. Hmm: Let’s hope the dough’s not made with Flint River water.

Fine: Detroit-style pizza won the 2012 Las Vegas International Pizza Expo. Don’t they know that what happens in Vegas is supposed to stay in Vegas?

Try to imagine Tony Manero strutting down Bay Ridge’s 86th Street eating two bricks of Detroit pizza at once.

Could the invading Michigander pies displace the classic New York treat? That’s just plain meshuga.