Quarterback Aaron Rodgers looks at his huddled teammates and delivers the orders.
"Left wide counter 394 PSZ four Z post."
At the clap, Green Bay Packers tight end Donald Lee has to think about this one for a split second.
Did he hear 394? Or was it 300?
"I really have to have my thinking cap on because that play I don't go out on a route, I have to protect the quarterback's backside," said Lee. "If I'm not paying attention, the D-end's got a free route to hit the quarterback in the back. If I happened to have a brain fart on that play, then the quarterback can get knocked out of the game."
What is the toughest foreign language to learn? Latin? Portuguese? Japanese?
Maybe it's Mike McCarthy's terminology for the West Coast offense.
There are an estimated 300 to 400 plays on offense and all of them have a different name. A few are straightforward; some are just outright bizarre.
Forget skinny post 85 or bailout check down 32. No that would be way too obvious.
One play is grizzly exit red left triple scat three zebra Y whip Z base.
And red robin plus cross outside fire zone; wing right over flop wallaby wide dog; exit blue slot left box 300 X ray corner; and red right flop V left 96 boomer tag.
And everyone on offense has to know the difference.
Now to be clear, for this story, every name of the plays has been jumbled with a substitute fake word. No need to give away the old family recipe. But you get the idea - the names of plays are crazy and long, with distinct cues for certain people, but the players have to know every one just the same.
Starting with Rodgers and the backup quarterbacks. It helps that Rodgers is one of the smartest players on the roster and with more than four years with McCarthy's system, he's got it down. The quarterback has to know what the other 10 players are doing on every play.
"You do have to memorize it all," said backup Matt Flynn. "In college, we'd call like one word and everybody would line up. This is totally different, detailed and specific; every word speaks to a different position. It's not like we're calling concepts."
But other players had to memorize the massive playbook one play at a time.
"I had to keep hearing it, hearing it and seeing it done," said practice squad running back Kregg Lumpkin. "So I can hear it and then visually see it as well. These were the longest plays I'd ever heard."
For an old veteran like Donald Driver, who has played for three different coaches, he's had to translate the play calls. What was three right slot X dagger for Mike Sherman is now zebra deep cross. Or was it blade? As long as Driver isn't confused, he just has to remember is go deep. And cross. We think.
Others have to work out the plays in practice.
"When they first start putting the plays in, they'll tell all the receivers in the huddle: If you don't get the play, yell check," said Lee. "I do that a lot. The plays sound like Chinese talk. I'm like, 'Check, check, check!' - I'm not the only one. A lot of guys do that. Usually the quarterback has to say the play about two or three times."
Even the defense has weird names that have forced the Packers to resort to creative ways of memorization. Linebacker Nick Barnett spent the off-season using flashcards to memorize plays. In other cases, assistant head coach Winston Moss gave the defense write-in playbooks.
"He put the O-line in so all I had to do was draw in the defense," said linebacker Desmond Bishop. "Once you see it on paper, then when you see it on the field the coach calls it live you can see how it is supposed to be executed.
"The play that really gets me is called a closed elephant zone Y. It's not really that long but it's kind of like a tongue twister sometimes."
After they know it, most players seem to listen closely to plays for their specific instruction.
The numbers tell which side the protection is going and then certain key words tell receivers to run certain routes, said Lumpkin.
"For me I've only got to listen to 50% of the call," said left guard Daryn Colledge. The defensive linemen don't have to bother with anything other than gap assignments.
But every word of the play means something different to everyone else. The skill position players really help themselves out if they know all of the plays, however.
"I learn the entire play vs. just my position, because otherwise you don't know what's going on everywhere else," said receiver Greg Jennings.
"You have to know all the plays because they might check an audible, which might not have been put in that week, but we went over during OTAs, so we still have to know," said Lumpkin.
Added receiver James Jones: "You've got to listen to everything because you want to know what other people are doing too. You have to listen in the huddle, read the defense - and then he could still check it!"
Given the challenges of the game, it is almost a miracle any time a play is called that all 11 men work in unison to pull it off.
It's to their advantage that Rodgers enunciates his words and has the deep voice to be heard through a noisy atmosphere. But sometimes even he is hard to hear.
"One thing I do is, instead of just getting in the huddle and trying to listen to the play, I actually get in and get close and squat down so I can look at his mouth to read his lips," said Lee. "That's how I really know what he's saying."
And that's half the battle.