Poles in the Right Half Plane

So Harry got his first sore throat this week. We will be returning to this tidbit of information later but first, a joke.

A flight is arriving in Prague one day when the pilot comes over the intercom and tells the passengers that they can get a wonderful view of the city if they look out the starboard side of the aircraft.

The plane promptly crashes.

Why?

The Poles were in the right half plane.

The above is an example of Control Theory Humor. I do not recommend it since it is invariably associated with lots of complex math. For instance, to "get" that "joke," you would need to read through the entire Wikipedia entry here and then maybe here pertaining to polar plots, imaginary numbers, transfer functions, and whatnot. Not worth it I say.

However, having said that, taking a course on Control Theory does make you look at the world a little differently. Let us return to the case of Harry's sore throat. Harry's throat is what would be referred to as the "plant." Harry's brain is the controller. So what happened with Harry's feedback loop?

Input to Plant- Irritation to Throat
Output from Plant - Pain
Input to Controller (Harry's Brain) - Pain
Output Command from Controller - Cry

Input to Plant - Increased Irritation to Throat
Output from Plant - Increased Pain
Input to Controller (Harry's Brain) - Increased Pain
Output Command from Controller - Cry Louder
.
.
.
Input to Plant - Increased Irritation to Throat
Output from Plant - Pain like you wouldn't believe
Input to Controller (Harry's Brain) - Pain like you wouldn't believe
Output Command from Controller - Scream Head Off, Writhe, Climb to Top of Crib, Fall Due to Gravitational Forces

Input to Plant - Irritation to Throat Gone, Pain to Noggin'
Output... You get the idea.

A long way of saying it was a long night.

UPDATE: Bonus points if you realize the joke is pretty silly. After all, only one Pole would need to be in the right half plane for the whole system to be unstable. Are we to believe only tourists are sold tickets for the seats in the right half of the plane while native Poles are stuck with the leftie seats? One Eastern European equivalent of Rosa Parks and they'd all be doomed.

UPDATE 2: Where did they bury the survivors?