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Before hopping on the balance beam for a typically dominant routine, Simone Biles does a subtle move.
Like many gymnasts, Biles chalks a mark on the beam, but hers appears different than the standard line on the four-inch wide beam.
Instead, Biles draws what appears to be a dollar sign on the beam.
Here was Biles writing it before winning gold in the all-around final on Thursday.
NBC Olympics
In 2014, Biles explained to the Pittsburgh Post-Gazette that she actually writes a line, like other gymnasts, but puts an "S" over it to show it's hers. Thus forming a dollar sign.
"You see, everybody puts their line on the beam, so I can never tell which one is mine. So, I put an 'S' on it, and it happens to turn into a dollar sign. People think I do it on purpose, but I don't."
All gymnasts make the mark as a point of reference in their routine, whether it's to start a trick or start a dismount. Biles' just happens to look more flashy.
However, there are other theories. Will Graves of the Associated Press says it dates back to the 2013 World Championships when the PA announcer mispronounced her name.
Simone puts $ in chalk on beam for her start point b/c announcer at 2013 worlds called her Si-Monay
As Mashable's Marcus Gilmer pointed out, the sign can be seen on the beam below:
Gregory Bull/AP
It's unclear if Biles is down-playing a bit of showmanship, or if her sign is really coincidental, but it only adds to the lure of "the greatest ever."