Photos by MATT GENTRY The Roanoke Times

Alyson Boehling (center) of Richmond asks a question Saturday during Kids' Tech University, a program that lets children ages 8 to 12 explore science, technology, engineering and math. Children will attend three more daylong sessions over the next three months..

Keith Devlin, "The Math Guy" on National Public Radio, answers questions Saturday at the Kids' Tech University program in the Graduate Life Center auditorium at Virginia Tech.

MATT GENTRY The Roanoke Times

Keith Devlin, National Public Radio's "The Math Guy," explains why there are spotted animals with striped tails but no striped animals with spotted tails Saturday at Kids Tech University in Blacksburg.

BLACKSBURG -- Jeda Folk totally destroyed the gingerbread woman.

"It's just a brown blob!" her partner, Hannah Fowler, shrieked as she looked at the image on the computer screen that the two were sharing Saturday at Virginia Tech's Math Emporium.

"I just put in the wrong numbers," Jeda said.

Such is the power of math.

The two 11-year-olds were among about 400 children, ages 8 to 12, who attended the first session of Kids' Tech University on Saturday. The Tech outreach program is designed to encourage children to take an interest in science, technology, engineering and mathematics.

The children will attend three more daylong sessions over the next three months. They include lectures and hands-on labs in various math and science disciplines.

Before learning the effects that inputting a few numbers could have on a computerized epicycloid design, a geometric function, the children listened to Stanford University professor Keith Devlin discuss the ways that math can answer real-world questions.

Devlin is known as "The Math Guy" in his role as commentator on National Public Radio's Weekend Edition. The question his lecture aimed to answer: "Why are there spotted animals with striped tails but no striped animals with spotted tails?"

He took his time getting there, describing the history of math and its inextricable link to science and the larger world.

"We use math to understand our world and ourselves," he said. "To do things, to build things, to understand things. ... It makes invisible things visible."

The answer to the question has to do with the shape of the animals when they are embryos -- the time most of them receive spots and stripes courtesy of a "battle" between melanin that creates dark spots or stripes on the skin and inhibitors in the animal's body that contain them.

He referred to a mathematical equation developed by University of Washington mathematician James Murray that explains patterns on animals when applied to the shape the animals are while in the womb. While the melanin is distributed randomly, the equation shows that the nature of the battle creates stripes over long and thin body parts and spots in broader parts.

"The leopard, in an embryo form, is sort of square, so you get spots," he said. "On the other hand, the zebra, if you look at the zebra in the womb, it's long and thin like a pencil. So you get stripes."

Invariably, long and thin parts of the animal's body -- such as tails -- are more likely to be striped.

While the children showed varying levels of interest during the lecture, when Devlin opened it up for questions, dozens of hands shot up, with some children jumping out of their chairs, eager to get his attention.

Some of their questions were relevant to the lecture: "Did any dinosaurs have stripes or spots?" Others not so much: "How does the sun warm the Earth?"

But Devlin answered as many as he could before lunch and the afternoon session at the Math Emporium. Tech professor Terri Bourdon gave the children a brief tutorial on computers and epicycloids -- produced by tracing the path of a fixed point on a smaller circle as it moves around a larger one.

She then turned the children loose on the computers.

They created their own designs and moved through a program with various characters -- such as the gingerbread woman and a "nasty bug."

While Jeda, from Staunton, was busy destroying her gingerbread woman, Sean DeHaven of Fincastle and William Tyler Davis of Troutville were a few monitors down, busy creating a bigger nasty bug.

"That's nastier!" 8-year-old William shouted after typing in a string of numbers to create a new version of the bug. "Can we print all this?"