You might not have noticed, but Chicken McNuggets are surprisingly consistent.

They’re among McDonald’s most popular foods, and they’re always exactly the same—right down to the shape. That consistency has helped to propel the product: McDonald’s introduced McNuggets in 1983, and the company was the second-largest retailer of chicken worldwide by the end of that year.

McNuggets are, of course, made from white meat chicken, along with a bevy of additional ingredients (more on that in a moment). The chicken is fried, then frozen, then reheated in restaurant fryers.

There are four McNugget shapes, according to McDonald’s website: the Boot, the Bow-Tie, the Ball, and the Bell. Why four shapes? We’ll let the company’s website explain.

“The 4 shapes we make Chicken McNuggets in was the perfect equilibrium of dipability and fun. 3 would’ve been too few. 5 would’ve been, like, wacky,” the site reads. “We also make them similar in size to ensure consistent cooking times for food safety.”

Business Insider reports that the chain also gears their McNuggets towards kids, adding that the shapes “make dipping more fun.”

McDonald’s claims to make McNuggets from all-white chicken breast meat.

The meat, along with its skin, is blended thoroughly, then formed and chilled. The nuggets are coated in tempura batter, pan-fried, and placed directly into a freezer. After an inspection, they’re sent off to the restaurants. Numerous inspections help to keep the chicken safe from salmonella and other diseases, and antimicrobial preservatives ensure that the nuggets arrive ready for the fryer.

However, the production process varies by country. A 2010 CNN investigation found that British nuggets contain fewer calories than their American counterparts. The American McNuggets also contained several additional preservatives.

McDonald’s explains the caloric deficit by noting that British nuggets are coated then fried. In the U.K., nuggets are fried then coated. As a result, American nuggets absorb more oil.

“You would find that if you looked at any of our core food items. You’d see little, regional differences,” said Lisa McComb, who handles global media relations for McDonald’s. “We do taste testing of all our food items on an ongoing basis.”

The strange shapes of McNuggets have helped to drive some unsavory rumors.

In 2012, a viral image suggested that McDonald’s mixes its McNuggets down into a “pink slime.” That’s not true; since 2003, the chain has used white-meat chicken, and the most popular image showing “pink slime” probably shows beef rather than chicken.

McDonald’s claims that their McNuggets contain many of the same ingredients that consumers would find at their local grocery stores. The company also claims to use a humane slaughtering process, that all of their birds are deboned by hand, and that their production facilities use “every part” of the chicken.

“The organs are used for pet food and animal feed, while the blood, feathers, and offals are sold to a rendering company that makes ingredients for animal feeds, fertilizers and markets such as cosmetics, rubber, and explosives,” the company’s site reads.

The video above shows an in depth look at how the popular meal was made. If you were worried about that pink goop like we were, it’s calming to know that wasn’t true.