The roster of people who actually registered and paid their dues ended up only numbering five. Seth and Quinn, Kiera, and two more men. The first was a gentle-looking man named Vince who enjoyed painting pictures of birds. The second was a burly man named Bjorn, the son of a minor nobleman from the island-continent of Vjiskald. The five of them moved into an empty classroom on campus. Their low numbers meant that they would need to outsource the actual construction of final components to a carpenter's guild in Lowtown.

"Our first order of business," Quinn said, "is to solve the problems that Seth currently has with controlling the machine." Seth dragged the oversized kite into the room for the other club members to look at. Kiera was taking detailed notes.

"The thought of sticking a spinning propeller on this thing terrifies me," Seth said. "It has a nasty tendency to want to nose-dive into the ground. It requires all my strength to control it. What I want, is for the kite to prefer to fly straight without me using any of my strength."

"So our first task is to design this preference into the shape of the kite itself." Quinn said. "But first we need to figure out why the kite tends to nose dive into the ground. Kiera, can you create wind?"

"Of course," she said.

"How strong can you make the wind blow?" Quinn asked.

"Strong enough to knock over this building definitely," Kiera said. "Maybe strong enough to destroy the Palace of the Spine?"

Quinn was astonished. Their building was built from stone and the Palace of the Spine was literally inside a mountain.

"Mother summer!" Quinn said. "Where did you learn to use magic?"

"Oh, the Eight Color Monastery on the north slopes of Spire Erika." Kiera said. "It's where Heritors go to school. I was in the same class as Empress Sasha and also Princess Lucia Aden of this city. The three of us, uh, got into a lot of trouble."

Quinn nodded. "Naturally. Kiera can you please create a tube of wind across this kite?"

Kiera did so, and Seth held the kite, attempting to hold it down. His muscles strained with the effort. Quinn lit a flare and allowed the smoke to blow across the wings of the kite.

"I am going to tip the nose down and show you," Seth said. "Make the wind faster."

As the nose began to dip, suddenly it accelerated towards the ground. Seth was ready and sized the kite before the nose smashed into the ground.

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"Exactly like that!" Seth said.

"I see the problem," Bjorn said. "It is a divergent function."

As massive and muscular as the man was, for some reason Quinn could not fathom, the man was one of the best mathematical minds that the school had seen in decades. "I have no idea what a divergent function is," Quinn said. "Can you explain?"

"Consider the angle of the nose at time T to be a function of the angle of the nose at time T minus one," Bjorn said. "This function is divergent and grows rapidly toward infinity. Basically, the wind hitting the top of the kite causes the nose to drop, exposing more of the top of the kite to be exposed to the wind. This is a death spiral. The angle grows fast and the speed at which the angle grows increased exponentially, at least. The exact function may be much more aggressive than exponential. I'm not sure."

"So how can we fix it?" Quinn asked.

"Subtraction," Bjorn said. "You just need to subtract off the function by a factor that is large enough to prevent the function from being divergent."

"That's a good idea," Seth said. "Can you explain that in a way that a five-year-old would understand?"

"I think what you need to fix your kite is a method of making the nose go up faster than it goes down," Bjorn said.

"Yeah," Quinn said. "That is the problem we are trying to solve. The question is how."

"One method of creating enough subtraction to converge a function is to make the amount subtracted proportional to the inputs."

"One thing that I noticed," Vince said, interrupting the conversation. "Is that your kite does not have a tail. Birds have tails, and I imagine that your flying machine needs a tail in order to fly."

Kiera was busy recording what they were saying. When the conversation stopped, she began playing with her pencil. In Quinn's estimation Seth would never be able to seduce the woman. Even Seth had quickly grown somewhat formal toward her, only speaking when asked direct questions. Though Vince and Bjorn seemed comfortable around her.

The woman held her pencil in between two fingers, in the center. She played with it, pushing the eraser down and the tip went up. Like a seesaw.

Like a seesaw.

"A seesaw!" Quinn said. Kiera perked up. "Kiera you are a genius!"

"Ah!" Bjorn said. "Yes, I know what you are exactly what you are thinking."

"We add a tail," Quinn said.

"I told you, we need a tail!" Vince said.

"A smaller wing on a boom, angled slightly down," Bjorn said. "The smaller wing in the back nose-dives first because it is angled slightly down, and causes the tail to dive down, and like a seesaw the front wing goes up. This would create an oscillation that is convergent." He nodded, satisfied. "I have solved the problem, right?"

"Don't forget that Kiera helped solve the problem," Seth said. Kiera looked... guilty?

The boys quickly hacked together a boom and a second smaller wing using wood and cloth. They attached the boom to the kite and repeated the experiment with Kiera's wind magic. The smoke blew over the wing, though as Seth tipped the nose of the kite, the kite refused to nose dive. In fact, when Seth released the kite it just sort of floated in one spot until it drifted to one side and fell out of the wind.

"This is it," Seth said. "If the thing wants to stay in the same spot while flying, then I can save my strength for control."

"Next," Quinn said. "We need to think about control. How do we control this thing? That will be the topic next time we meet. For now, I need to draft a design and send it to our carpenters. We will want to test this new design before we jump to conclusions."