And taking all his directions from the black line on the bottom of a pool.
There's no need to restart the debate over whether Michael Phelps is the greatest Olympian ever, at least not on the night he walked off the pool deck and out of competitive swimming for good. Or so he said.
"I could probably sum it up in a couple of words: I did it," Phelps said when asked what he would write about Saturday night in the journal he's keeping.
He seemed certain those are his last words on an Olympic career like no other. Twice as many golds (18) and more medals (22) than anyone else. Bob Bowman, who coached the swimmer since he was 11 and became a kind of surrogate when Phelps' parents divorced, sounded almost as certain. That probably explained why he was fighting back tears the whole night.
"I think we've had a great end to a great run and there's not much more he can do. I guess if he finds after a few years he's searching for something and thinks he can find it in swimming, he could look at it. But I don't think he will," Bowman said. "I think he's ready to explore other things. He's done all he can do here."
But a few minutes later, someone asked the coach how much longer the 27-year-old Phelps could compete at a world-class level. Bowman didn't have to think long. His voice got a lot steadier, too.
"He could probably go eight years." he said. "He'd have to swim shorter events. I don't think he'd swim a 400, but physically, I don't think he would be limited that much."
Do the math, keeping in mind the strides made in conditioning older athletes in recent years. Phelps would 31 in Rio in 2016, and 35 by the time the International Olympic Committee pitches its tent for another Summer Games four years after that.
Former U.S. teammate Gary Hall won the 50-meter gold at age 29 at the Athens Olympics. Dara Torres, who was the only swimmer on either the U.S. men's or women's teams to compete in five Olympics, as well as the oldest to win a medal — three silvers at 2008 Beijing Games — was 41 when she finally bowed out. And she narrowly missed qualifying for the team here.
The only math Phelps was interested in on this night was his own.
"One of the biggest things that I've always said to myself is I'll never swim at the age of 30. I wanted to be done before I hit the age of 30. One of the biggest things is I know if I go three more years, then you just go another one," he said.
"There are other things that I want to do in my life," Phelps added, "and I'm not sure staring at a black line for four hours a day is one of those."
He's been mentioned as a TV analyst. Phelps said he wants to play more video games, poker and golf. Travel. Go cage-diving in Australia with great whites.
Those who remember how his last two extended getaways went might argue that the rigours and routines of the sport suited Phelps' personality well. Even swimming with sharks, in fact, sounds tame compared to the hot water he landed in after the last two Olympics. Following Athens, it was a DUI; after Beijing, Phelps was photographed at a party holding a bong.
"If there's someone who can tell me they have never made a mistake in their life then I'll applaud them," Phelps' mother, Debbie said. "Mistakes are part of growing up. ... I'm not saying it's right. I'm not saying it's wrong. But it happens all over the place."
But it isn't just a lack of structure that her son will have to deal with. There's that competitive jones that's driven Phelps from the time he tagged along with his sisters and wound up racing other 7-year-olds in a Baltimore pool.
"He went and played cards with my mother," Debbie Phelps recalled, "and even then, he's got strategies in place how he was going to beat her. And I'm thinking, 'She's 87 years old, Michael. Let your grandmother win.'
"I'd like to be in his head sometime," she added a moment later. "He seems to know exactly what he has to do."
What Phelps wants to do at the moment is stop. As he got up to leave the post-meet news conference, someone asked the other members of the relay team whether they genuinely believed he was retiring. Phelps didn't give Matt Grevers, Brendan Hansen and Nathan Adrian a chance to respond. As he walked behind each one, he kept repeating, "Yes, yes and yes."
Let's see how long that lasts.
Jim Litke is a national sports columnist for The Associated Press. Write to him at jlitke(at)ap.org and follow him at Twitter.com/JimLitke.