"some of the most popular items" on what it calls the company's "not-so-secret menu." "Animal Style" is one of the most popular "secret" styles; in addition to the standard toppings, Animal Style burgers include mustard fried onto each meat patty, pickles, grilled onions, and extra spread. "3×3" (pronounced 3-by-3), "4×4", or variations of "m" × "c", refers to a burger with a varied amount of meat patties, "m", and slices of cheese, "c": e.g. a burger with six meat patties and three slices of cheese is a "6×3". The In-N-Out "secret menu" section of the website only mentions the "3×3" and "4×4", which are registered trademarks of the company. Until 2004, In-N-Out accommodated burger orders of any size by adding patties and slices of cheese at an additional cost. However, on October 31, 2004, a group of friends ordered a 100×100 from a location in Las Vegas, Nevada, posting photos on the web of the burger with Tony Hsieh, CEO of Zappos. Once word got out of the incredibly large sandwich, In-N-Out management disallowed any sandwich larger than a 4x4. In-N-Out has two low carbohydrate offerings. "Protein Style", introduced in the 1970s, replaces the bun with large leaves of lettuce; while the "Flying Dutchman" is a 2×2 with no bun, no vegetables, and no spread with the cheese slices placed between both patties. Health.com rated the protein-style sandwich as the best low-carb sandwich in the United States. They also offer a grilled cheese sandwich (a hamburger with the patty replaced by two slices of cheese). Onion styles In-N-Out's burger customization offers customers a choice of six different onion styles – three variations of the two ways that onions can be cut (sliced versus chopped). With onion or chopped onion – standard placement, onion is put on top of the meat/cheese as the burger is cooking. Raw onion or raw chopped onion – onion is cold and more crisp, placed on top of the spread. Whole grilled onion or grilled onion – onions are grilled until brown, placed on top of meat. French fries In-N-Out uses the Kennebec variety of potato for its fries and prepares them on-site as opposed to purchasing them pre-made from other companies. The company's french fries are cooked in "100% pure, cholesterol-free sunflower oil." Fries can also be cooked to order, with cooking times ranging from "light" to "extra well done". Beverages The company offers lemonade,