Federal Reserve Skateboard: A Short Story

(Written after sitting in a car for five hours listening to financial news stories.)


Damn these subprime lenders, thought Fed Chairman Ben Bernanke, barely keeping his balance on the wobbling skateboard. We can’t afford more debt. He snapped a grappling-hook-tipped quarrel into his crossbow as the skateboard slowed. When the country owes trillions and is asking for more, its shadowy creditors start calling in favors.

The crossbow twanged, carrying his climbing rope up the side of the Federal Reserve building. As he began his ascent, he reflected on the years past. I inherited a broken system, he insisted to himself. We’re simply doing what’s required to prevent a catastrophe. It’s not my fault.

He tossed his skateboard over the parapet and hauled himself over. He dropped six feet to the roof, landed heavily on the board, and trundled on into the night.


From her perch in a tree across the street, the blogger watched through her blogoscope as Bernanke disappeared over the wall. She spoke quietly into her radio: “Subject is in the haybarn. The chickens are in danger of roosting.”

“Roger that,” came the reply. “Deploying Agent Harpsichord.”


Inside, Bernanke moved along the wall like a shadow, elongating and contracting as the light sources shifted around him. In the midst of a sea of filing cabinets, he froze. He sniffed the air, then dropped to his knees, licked the floor, and paused. Yes, he thought, Greenspan was definitely here.


The blogger had waited five minutes and was starting to get impatient. She picked up the radio. “Situation imminent. Pass the ducklings through the snorkel. Repeat: Pass the ducklings through the snorkel.”

“We are go for mode Sinatra,” replied the commander. “Reticulate core and set throttle to ‘cryptic’. Prepare to jitterbug.”


Bernanke forced the door on yet another inner office, realizing too late that the light was on inside. The chair in the corner swiveled around, and Bernanke found himself face-to-face with Alan Greenspan. There was silence for a moment.

“You won’t get away with this,” said Greenspan, rising to his feet. “The Fed is subject to general congressional oversight. But you never understood that, did you?”

“Congress sold out the country, not me,” replied Bernanke. “Don’t shoot the messenger.”

“I wasn’t planning to,” said Greenspan. He flicked open a switchblade.


The blogger peered once more into the eyepiece of her blogoscope. She threw the switch labeled “overlay building schematics.” The external view of the building disappeared, but instead of blueprints, she was presented with a green puzzle piece. “This view requires the Adobe Flash Player plug-in. Do you want to search for this plug-in now?”

Shit, she thought.


Bernanke, trying not to slip in the patches of blood on the floor, struggled with Greenspan. The older man moved like a snake that moved like a former Fed Chairman who moved like a ninja. At last, Bernanke got a solid grip on Greenspan’s collar and hurled him through the fourth wall, knocking you to the ground.

Improvising a tourniquet from the remains of the snake left over from the earlier simile, Bernanke moved on through the hallways.


The moonlight-bathed roof of the Federal Reserve building fell suddenly into shadow. A pair of night watchman looked up in alarm to see what had occluded the sky.

“Is that …” one whispered to the other, “… is that a blimp?”


Bernanke reached the central vaults, accessed the Gibson mainframe, and began transmitting the requested files to his distant masters. He didn’t hear the gentle thud on the rooftop, the muffled explosive charges, or the sound of the door opening behind him. But at the last minute some sixth sense kicked in. He spun around just in time to see a golf-ball-sized lump of gold rapidly expanding in his vision. It struck him in the forehead, and he collapsed to the ground like a burlap sack full of scrapple.

Congressman Ron Paul retrieved the gold nugget from the floor and returned it to his satchel. “Try that,” he said, donning his sunglasses, “with a fiat currency.” He spun on his heel, cape swirling behind him, and swept from the room.

Read more of these adventures in the thrilling new novel, Ron Paul and the Chamber of Commerce — in bookstores now!

The Goddamn Airplane on the Goddamn Treadmill

Sorry for the forum/blog downtime today. Many things went wrong during davean’s heroic upgrade. (I blame the LHC.)

Feynman used to tell a story about a simple lawn-sprinkler physics problem. The nifty thing about the problem was that the answer was immediately obvious, but to some people it was immediately obvious one way and to some it was immediately obvious the other. (For the record, the answer to Feynman problem, which he never tells you in his book, was that the sprinkler doesn’t move at all. Moreover, he only brought it up to start an argument to act as a diversion while he seduced your mother in the other room.)

The airplane/treadmill problem is similar. It contains a basic ambiguity, and people resolve it one of a couple different ways. The tricky thing is, each group thinks the other is making a very simple physics mistake. So you get two groups each condescendingly explaining basic physics and math to the other. This is why, for example, the airplane/treadmill problem is a banned topic on the xkcd forums (along with argument about whether 0.999… = 1).

The problem is as follows:

Imagine a 747 is sitting on a conveyor belt, as wide and long as a runway. The conveyor belt is designed to exactly match the speed of the wheels, moving in the opposite direction. Can the plane take off?

The practical answer is “yes”. A 747’s engines produce a quarter of a million pounds of thrust. That is, each engine is powerful enough to launch a brachiosaurus straight up (see diagram). With that kind of force, no matter what’s happening to the treadmill and wheels, the plane is going to move forward and take off.

But there’s a problem. Let’s take a look at the statement “The conveyor belt is designed to exactly match the speed of the wheels”. What does that mean?

Well, as I see it, there are three possible interpretations.  Let’s consider each one based on this diagram:

1. vB=vC: The belt always moves at the same speed as the bottom of the wheel. This is always true if the wheels aren’t sliding, and could simply describe a treadmill with no motor. I haven’t seen many people subscribe to this interpretation.

2. vC=vW: That is, if the axle is moving forward (relative to the ground, not the treadmill) at 5 m/s, the treadmill moves backward at 5 m/s. This is physically plausible. All it means is that the wheels will spin twice as fast as normal, but that won’t stop the plane from taking off. People who subscribe to this interpretation tend to assume the people who disagree with them think airplanes are powered by their wheels.

3. vC=vW+vB: What if we hook up a speedometer to the wheel, and make the treadmill spin backward as fast as the speedometer says the plane is going forward? Then the “speedometer speed” would be vW+vB — the relative speed of the wheel over the treadmill. This is, for example, how a car-on–a-treadmill setup would work. This is the assumption that most of the ‘stationary plane’ people subscribe to. The problem with this is that it’s an ill-defined system. For non-slip tires, vB=vC. So vC=vW+vC. If we make vW positive, there is no value vC can take to make the equation true. (For those stubbornly clinging to vestiges of reality, in a system where the treadmill responds via a PID controller, the result would be the treadmill quickly spinning up to infinity.) So, in this system, the plane cannot have a nonzero speed. (We’ll call this the “JetBlue” scenario.)

But if we push with the engines, what happens? The terms of the problem tell us that the plane cannot have a nonzero speed, but there’s no physical mechanism that would plausibly make this happen. The treadmill could spin the wheels, but the acceleration would destroy them before it stopped the plane. The problem is basically asking “what happens if you take a plane that can’t move and move it?” It might intrigue literary critics, but it’s a poor physics question.

So, people who go with interpretation #3 notice immediately that the plane cannot move and keep trying to condescendingly explain to the #2 crowd that nothing they say changes the basic facts of the problem. The #2 crowd is busy explaining to the #3 crowd that planes aren’t driven by their wheels. Of course, this being the internet, there’s also a #4 crowd loudly arguing that even if the plane was able to move, it couldn’t have been what hit the Pentagon.

All in all, it’s a lovely recipe for an internet argument, and it’s been had too many times. So let’s see if we can avoid that. I suggest posting stories about something that happened to you recently, and post nice things about other peoples’ stories. If you’re desperate to tell me that I’m wrong on the internet, don’t bother. I’ve snuck onto the plane into first class with the #5 crowd and we’re busy finding out how many cocktails they’ll serve while we’re waiting for the treadmill to start. God help us if, after the fourth round of drinks, someone brings up the two envelopes paradox.