Any American old enough to wield a spoon can probably pick out a Cheerio in a lineup of other breakfast cereals, thanks to its iconic “O” shape. But what may come as a surprise is that General Mills, the creator and manufacturer of Cheerios, tested out more than ten shapes and sizes before selecting the now-recognizable doughnut shape that floats in cereal bowls worldwide. The humble Cheerio was not always destined to be an “O”—it could have been a spiral, a star, or a sphere.

The Cheerio got its recognizable shape thanks to food science innovator Lester Borchardt and his team at General Mills Research Laboratories. In 1937, James Ford Bell, the company’s president, chairman, and founder, tasked his employees to create a ready-to-eat oat cereal that would eventually become “Cheerioats.” (Long story short, the cereal’s name was changed to Cheerios several years later due to an unnamed competitor’s lawsuit over the word “oats.”)

The Cheerioats project was an outgrowth of another General Mills brand: Kix. By 1939, Borchardt and his team began testing the oat-based recipe by creating different shapes and sizes using dies, cookie cutter-like devices used in manufacturing to cut material into specific forms. The Minnesota-based company tested numerous options, including a sphere, a six-pointed star, a five-pointed star, a four-pointed star, a three-pointed star, a thin-walled doughnut, a thick-walled doughnut, a dumbbell, a spiral, and a square. The result was the first ready-to-eat oat cereal on the market that was also made in the shape of a doughnut.

“Results favored the doughnut shape as being the most unique and consistent with good package fill,” says Jessica Faucher, corporate archivist for General Mills. “The cereal needed to be light enough to get eight ounces into the package. Also, the doughnut shape proved successful during testing runs when the cereal was being manufactured.”

When introduced to the public in 1941, there was no other brand on the market that came close to resembling Cheerios, according to General Mills. And much to the chagrin of parents everywhere, children began clamoring for this newfangled cereal the way kids today beg for the latest smartphone upgrade. Advertisements at the time praised the unique Cheerio shape, and highlighted the convenience of a product that could go from box to bowl without being cooked. One advertisement in particular boasted, “Cheerioats doesn’t even look like any breakfast food you ever saw before. We blow it out of guns in the clever shape of little miniature doughnuts... fat and round and toasty-brown.”

If the doughnut shape was something so new and spectacular and groundbreaking in the cereal industry at the time, why didn’t General Mills take the time to trademark it? After all, over the years numerous O-shaped cereals have taken up valuable shelf space at grocery stores, including Froot Loops and Apple Jacks (both made by Kellogg’s), and the Quaker Oat Company’s Honey Graham Oh’s (a brand that’s now owned by Post Cereals). And that’s not even mentioning the multitude of now defunct cereals like Dunkin’ Donuts Cereal, Urkel-Os, Freakies, and Cap’n Crunch’s Choco Donuts, which have all departed to the giant cereal bowl in the sky (R.I.P.). Faucher chalks up the lack of trademarking to it being, “so long ago, we don’t have any information on why we didn’t seek trademark protection.”

In General Mills’ defense, trademarking intellectual property was still a relatively new concept in the United States at the time of the brand’s introduction. In fact, the US government didn’t even pass the Lanham Act, a federal statute that governs trademarks, until 1946, five years after Cheerioats hit the market.

So, would Cheerios have been such a runaway success if it were, say, shaped in the form of spirals, stars, or even dumbbells? After all, it is the most popular breakfast cereal in the United States, with nearly $1 billion in sales in 2014 alone, according to Euromonitor International, a strategic market research firm. Plus, it’s hard to believe that the shape can take all the credit for its popularity. Ask any toddler, and between mouthfuls he or she will confirm that it tastes delicious, too.

Here’s Faucher’s take: “Because Cheerioats had been successful in every test to which it was subjected, [General Mills] knew it had a fine product. It’s difficult to predict what other shapes might have led to. Research and development of the product helped to ensure its continued success.”

Plus, “Cheeri-spirals” just doesn’t have quite the same ring to it.