After winning the Grand Prix Final for the fourth straight year, Yuzuru Hanyu of Japan was playing around during practice for the event's exhibition gala.
To a men's figure skater in 2016, this is what "playing around" means: He tried a quadruple salchow, followed by a half loop, followed by...another quad salchow.
Yes, he fell on the second salchow, but still: a quad-quad combination?
"He gets pretty excited/competitive on those practices," said Hanyu's coach, Brian Orser, in a text message. "I saw a quad axel once on one of those practices!"
Maybe the exclamation point is no longer even necessary in an era when the quad jumping progression has gone from arithmetic to exponential.
So what's next?
"Back flip to one foot to a quad salchow," wrote four-time world champion Kurt Browning in a text message unadorned by any emoji or form of punctuation -- suggesting he was not playing around.
After all, back when quadruple jumps still seemed revolutionary, Timothy Goebel already was talking about the possibility of quintuples.
"I think anything is possible," Goebel told me in 2000, two years after he had become the first skater to land a quad salchow. "I don't know if the quintuple will happen in my skating career, or even the next generation, but I'm sure someday, someone will do it.
"No one 15 years ago thought a quad would be possible. The sport is changing real fast. I don't think anyone knows how far it will go."
There have been no quints yet, but the quad has become so routine in elite men's skating that the athletes are finding new ways to make such jumps seem revolutionary again.
This October, at the Autumn Classic International in Montreal, Hanyu became the first to land a quad loop in competition. Last April, at the Team Challenge Cup in Spokane, Washington, his compatriot, Shoma Uno, became the first to land a quad flip in competition.
Both were scheduled to skate this week at the Japanese championships in Osaka, until Hanyu announced Wednesday that he would not compete because of the flu. Even with him and two other quadsters, Daisuke Murakami and Sota Yamamoto, also absent from the event, there still could be a half-dozen men prepared to try at least one quad in the free skate.
And at this week's Russian championships, the field includes two guys who each landed a quad at the recent Junior Grand Prix Final: Dmitri Aliev, 17, and Alexander Samarin, 18. Aliev and Samarin won gold and silver, respectively.
In the free skate at the recent Grand Prix Final, the top five men in the six-skater field combined to cleanly land five of the six types of quads. Both Hanyu, 22, and 17-year-old Nathan Chen of the U.S. landed three different types (Chen went clean on all four of his quads.)
The only quad missing was the 4 1/2-revolution axel, which no one has landed in competition. But it was a subject of conversation in the press conference after the free skate.
"I don't know how soon it will be, but it would be amazing to see," Chen said.
Who could be the first to land one?
"Yuzu has a beautiful, easy axel, so I'm sure it's an achievable goal for him," Chen said. "It will be a goal for me in the future, but I want to have a consistent triple axel first."
Hanyu said trying a quad axel in a program has been his dream since he began skating.
"I want to practice quad axel, and if it's possible, I will put it into competition," Hanyu said.
Browning, credited with landing the first successful quad in competition (at the 1988 World Championships), said he tried a quad axel in practice for a few days "about a million years ago."
"Competitive season was coming, so we stopped trying it to prevent injury, and it did not seem like it was going to happen for me," Browning said.
He thinks Hanyu will have a chance if he could get more height on his triple axel.
Height is one of the two factors governing how many revolutions a skater can make in the air. The other is how fast a skater can spin. The athlete's strength-to-weight ratio figures in both areas, as does the weight of skate boots and blades -- a significantly lighter skate would allow for a significant increase in hang time -- but changes in equipment have lagged behind the rapid advancements made in men's skating.
According to a French study done 20 years ago, the maximum rotation speed is 2,000 degrees per second, which would allow a skater to make 5 1/2 revolutions if he could stay in the air for a full second and keep spinning at full speed.
But few skaters can jump high enough to stay in the air more than 0.7 seconds.
And a skater loses rotation speed on the axel takeoff, which involves one leg swinging wide, a poor position aerodynamically. That is why a quintuple jump may be possible before a quadruple axel.
James Richards, a biomechanist at the University of Delaware, told LiveScience.com he does not think a quintuple is possible.
"To do a quint, we would have to have somebody built like a pencil," Richards said.
Orser has an 11-year-old, Stephen Gogolev, whom the coach said already can land three types of quads: salchow, toe loop and lutz.
"I think this generation of skater is raising the bar quickly," said Scott Hamilton, who won the 1984 Olympics without a triple axel. "It's incredible that these advances happen seemingly overnight."
There is a simple reason why skaters are pushing the quad envelope: Quads bring a lot of points. Their base value has even been increased since 2010, when the quad explosion really took hold, by increments ranging from 5 to 10 percent, depending on the type of jump. If that weren't enough incentive, add this: a fully rotated quad can get full base value even if the landing is two-footed or results in a fall. Put simply, any fully rotated quad with a fall is worth more base points than every triple jump except the axel.
If Hanyu could pull off the quad combination he has been toying with, it would be worth 21 points. At the Grand Prix Final, where he won the free skate and was second overall, Chen scored 58.9 of his 113.13 technical points on his four jumping passes (of eight) that contained quads.
Given the current scoring system, a skater trying for a high finish would be wise to try as many quads in a free skate as he feels confident about landing.
"Where does it stop?" mused Goebel, the 2002 Olympic bronze medalist and first to land three quads in a free skate. "I think four will be the plateau, at least leading into 2018. There are a few that could do five: Hanyu with two sals, two toes, a loop, or Chen with two lutzes, two toes, a flip.
"However, I think the mental aspect is going to be a limiting factor. That's A LOT of responsibility to take on mentally. From my experience, going from one triple axel to two in a free skate was a big mental hurdle, and it was the same for adding the second or third quad."
Chen attempted five quads (of four different types) at this year's Finlandia Trophy, getting full base value on all five but negative Grades of Execution on four, including two with falls. Two came in the bonus portion (second half) of a free skate he won, despite the mistakes, over three-time world champion Patrick Chan of Canada.
"The biggest thing for me is, where do I recover, where do I rest between the quads," Chen said. "We've been playing with different setups where I do quads early, do quads late, do quads in between. At the moment, the strongest scenario for me is to do the four quads at the beginning."
And who knows where this all will end?
(This article originally appeared on icenetwork.)
Quad Revolution Timeline
1988: At the world championships, Kurt Browning of Canada gets credit for the first quad (quad toe loop).
1991: At the world championships, Elvis Stojko of Canada lands the first quad in combination (quad toe loop-double toe loop).
1994: Min Zhang of China lands the first quad at an Olympics (quad toe).
1997: At the Champions Series (now Grand Prix) Final, Stojko lands the first quad-triple combination (quad toe loop-triple toe loop).
1998: At the Junior Champions Series (now Junior Grand Prix) Final, Timothy Goebel of the United States lands the first quad salchow.
1998: The ISU Congress votes to allow quads in the short program.
1999: At the Four Continents Championships, Zhang lands the first quad in a short program (quad toe).
*At the Nebelhorn Trophy, Ilia Klimkin of Russia is first to land two different quads in a program (quad toe loop, quad salchow).
*At Skate America, Goebel is the first to land three quads in a program (quad salchow-triple toe loop, quad toe loop, quad salchow).
2002: Gold medalist Alexei Yagudin of Russia (quad toe-triple toe) and bronze medalist Goebel (quad salchow-triple toe) land the first quads in an Olympic short program.
2011: At the Colorado Springs Invitational, Brandon Mroz of the U.S. lands the first quad lutz.
2016: At the Four Continents Championships, Boyang Jin of China is the first to land six clean quads in one competiton: two in the short (quad lutz-triple toe loop; quad toe loop) and four in the free skate (quad lutz, quad salchow, quad toe loop-double toe loop, quad toe loop).
*At the Team Challenge Cup, Shoma Uno of Japan lands the first quad flip.
*At the Autumn Classic International, Yuzuru Hanyu of Japan lands the first quad loop.
Sources: 2017 U.S. Figure Skating media guide, International Skating Union releases, news reports.