How does Simone Biles do what seems impossible?

On Sunday, Simone Biles set yet another astounding record. With gold medals on both the balance beam and floor exercise, she earned her 24th and 25th world championship medals, breaking the legendary Vitaly Scherbo's record for world medals in history.

With golds in the team, all-around and vault as well, it's been a historic week at the world championships in Stuttgart, Germany. But it's not only medal counts that make Biles unique. A week ago, in the qualifying rounds, Biles competed two eye-popping, never-done-before skills: a double-twisting double back dismount off beam and a triple-twisting double back on floor. She now has four original skills named after her in the code of points.

AND ANOTHER ONE! The greatness never ends.

The double double beam dismount is now named 'The Biles' after @Simone_Biles performed it during her routine at the World Championships. #Stuttgart2019 pic.twitter.com/rPvMy0DxRU

— Olympic Channel (@olympicchannel) October 5, 2019

"She is, without question, the most dominant gymnast in the history of the sport," said two-time Olympic gold medalist and current ESPN gymnastics analyst Bart Conner. "She's doing the most difficult gymnastics ever attempted, and she does it effortlessly. She's the perfect gymnast for the perfect time."

So what is it exactly about Biles that makes her so much better than everyone else? Just what is the secret sauce to her achievements? As you might imagine, it's not just one thing, but a combination of elements that make Simone, Simone.

As Kathy Johnson Clarke, two-time Olympic medalist and current ESPN broadcaster, put it: "She is really the perfect storm."

Her height and strength make her ideally suited for power

Conner points to Biles' high strength-to-weight ratio as ideal for the sport. Much like Michael Phelps is often considered to have the perfect build for swimming due to his long torso and wingspan, the 4-foot-8 Biles could have the perfect body for high-difficulty skills in her sport. With her small stature, she is able to do more in the same amount of time as others who might be taller or with a lower strength-to-weight ratio. While not all gymnasts' heights are publicly released, for comparison, two of Biles' U.S. teammates at worlds, Kara Eaker and Jade Carey, are listed at 5-0 and 5-2, respectively.

Dr. David Young, a physics professor at Louisiana State University, credits Biles' ability to maximize her time in the air -- twisting and flipping ultra-efficiently-- and finding the perfect launch angle (called the "set" or "block" in gymnastics) to conserve the kinetic energy she gains during her lead-up skills.

"What sets her apart is her strength, balance, coordination and muscle control that produce faster rotation rates once she's in the air. Of course, she then needs the skill, timing and training to know when to unwind all that rotational energy and stick the landing," he said.

He calculates Biles' takeoff speed at 14.7 mph, and says that with her current rotation speed, he believes from a strictly physics perspective that she could actually add another half twist to the skill on floor. (A big caveat here, though: The gymnastics reality of that would be incredibly tricky, since Biles would then be forced to land the skill in the opposite direction, meaning she couldn't see the ground before she lands. So while the laws of physics may show she could probably complete that skill into a training pit, landing it on a competition floor would be an entirely different feat.)

She has some of the best "basic" skills of any gymnast

No matter how genetically blessed Biles may be, it would all be for naught if she didn't have incredible technique and a strong gymnastics foundation. While Johnson Clarke is impressed with Biles' triple-double, she thinks what she does going into the skill is just as important.

"She has extraordinary technique in the lead-up skills that allow her to do those tumbling passes and that beam dismount," she said. "Her round-off, back handspring ahead of the triple-double is phenomenal technically. It's extraordinary, it's to-die-for, it's perfect.

"A lot of people don't have that technique, but then on top of that, there is really no one else who has that perfect of a technique combined with her explosive, quick power. That amplifies her technique. The way she reaches into the round-off, the line, how quickly she gets her arms back out of the round-off ... and then her back handspring is the shape of a perfect rainbow. It's textbook."

Here's a slow-mo view of that round-off, back handspring (and triple-double!).

The triple double never gets old. #Stuttgart2019@Simone_Biles @USAGym @gymnastics pic.twitter.com/4Jx1H2i9QL

— Olympic Channel (@olympicchannel) October 1, 2019

Biles' current technique, according to Johnson Clarke, is the result of the training she had in her early days in the sport. She points to videos she's seen of Biles as a technically-sound seven or eight-year-old. That foundation provides a huge advantage when learning and attempting new tricks.

"I never thought I would see a triple-double in my lifetime, and she does it so flawlessly," Conner said. "It's only because she has the technique and the form -- that allows her to do everything else. She's gifted with power, but her technique is so spot on. I think for the casual fan that's hard to identify because they just see her flying through the air, but it's so much more than just a god-given gift. It's hard work, dedication and a commitment to strong form."

(Note: Others, including her national teammates Jade Carey and MyKayla Skinner, have shown their attempts at the triple-double in training, but no one else has attempted it in competition.)

She has the mental game to back up her physical ability

According to her coaches, Biles is also exceptional at the often-overlooked side of gymnastics. "She is so strong mentally," said one of Biles' coaches Cecile Canqueteau-Landi. "She won't give up, she focuses well and she's very hard on herself."

And beyond the mental traits she needs to push herself to be the best of all time, there's also fear to overcome. She is, after all, attempting skills no one else has ever done in competition. She had her doubts about both of her new skills before fully committing to competing them, but she credits Cecile and her other coach Laurent Landi (Cecile's husband) for creating an atmosphere of belief.

"I actually had to -- not be forced -- but [Laurent] had to help me a lot," she said. "I had done them in pits and stuff, but I never thought I would be able to compete them one day, so Laurent and Cecile helped me a lot in believing in myself so that I could compete them, and here we are. I feel like it's not real, but it is. I've done a triple-double for a couple of years in training, just playing around, as well as the double-double on beam when I was younger, but never thought it would be in a routine until now."

Cecile believes the strong relationship they have with Biles allows her to try new things, because she knows they have her best interests at heart.

"Once the trust was built between us and her, it made it easier for her to believe she could do it," said Cecile. "We had to show her and explain what it would take to make it happen, and once she knows the plan, she tries it for fun, and then realizes that it is a realistic skill she can successfully do, and the rest follows."

It all adds up to an almost unbeatable score in competition

The code of points was overhauled in 2006, and now it relies on an open-ended scoring system that combines the difficulty (D) score and execution (E) score to get to the total score. Many feel it has also created the possibility for someone to get light years ahead of the rest of the competition by dramatically boosting their difficulty numbers.

Right now, Biles is that someone.

In worlds qualifications, Biles had a combined D score of 25.3. U.S. teammate Sunisa Lee, at 23.7, was the next highest in the competition. That means that even if Biles fell off the apparatus (a 1.0 score deduction), she would still beat Lee, by a long shot, just because of her starting advantage. In fact, at the 2018 worlds, Biles did exactly that. Suffering from kidney stones, she won the all-around title by 1.693 points over Japan's Mai Murakami, despite counting falls on vault and beam.

"It doesn't take Einstein to figure out, you want all of your skills and connection values in a routine to be as high as they possibly can be," said Johnson Clarke. "That is the goal in today's system. So obviously everyone is going to jam-pack a routine with the hardest, most badass tricks so they can get to those big scores. And then with Simone Biles, she takes it to another level -- she's adding letters to the scoring alphabet. It's a different sport than it was [before] due to the scoring system, but she's in a category of her own and found a way to get the highest possible score she can."

How does she accumulate such a high difficulty score? It's a complicated system, but the shortened version is this: Each skill in the code of points has a value, ranking from A (the easiest) to J (currently the most difficult), and each letter has a point value associated with it, one tenth more for every letter in the alphabet. So the higher rated the skills in a routine, the higher the potential difficulty score.

Biles officially submitted her new skills to the International Gymnastics Federation (FIG) to be evaluated ahead of worlds and given a point value. The triple-double was given a J, but the double-double dismount off beam ignited controversy when it received only an H rating. Biles strongly disagreed with the decision and made her feelings public in this tweet. But the FIG's women's technical committee cited safety concerns, saying its decision took into account an "added risk in landing ... including a potential landing on the neck."

Even with the lower valuation, Biles will still lap the world championships field with her difficulty score. There is no one else competing a trick with a J value on any event. And while some gymnasts do high difficulty at the expense of execution, Biles holds her own on the execution score due to her impressive technique. In fact, she led the field in qualifications in E score as well, though by a smaller margin of 34.632 to Chinese gymnast Liu Tingting's 34.165.

The strategy has been proven: With good execution scores and ridiculously high difficulty scores, Biles creates an almost unreachable standard for her competitors.

"[In] the current state of the sport, there's a huge premium for high degree of difficulty," said Conner. "It gives you an enormous buffer, in case you struggle with other areas. And because Simone is so good at so many of those difficult elements, at this window of time in our sports evolution, she's made herself almost unbeatable."