Soon, each had created a crane that flapped its wings when its tail was pulled.
"The great thing about origami is that you just keep doing the same thing over and over again," the full-time origami artist said.
The next project was a small paper balloon.
"When I lived in Brooklyn, I made these," Walker told the children. "I lived on the fifth floor, and I filled them with water and dropped them from the roof. I'm not telling you to do that."
Many origami figures start with a triangle, but the balloon started with a rectangle.
On display in the gallery was a large board of multicolored stars Walker had made, and a box of small, shiny frogs, turtles and other animals. The favorite with the children seemed to be a set of "Hear No Evil, See No Evil, Speak No Evil" orangutans. Many of the designs are of his own creation.
Madison Caldwell, 8, of Chambersburg, said she has done origami before at her school, Andrew Buchanan Elementary School. Her favorite part of origami is "when it comes out, how awesome it looks."
David Jarrett-Rico, 10, has an origami set at home. The Hooverville Elementary School fifth-grader said he likes "what it turns into," holding the yellow crane he made.
Amber Leisher, 10, likes that "you can make unique stuff. Every time, it's something different."
When Amber's twin, Jena Leisher, asked Walker for advice on going further with origami, he told her, "Do the easy stuff first. Look at the picture, but don't read the directions because they'll confuse you. Read them after (you make the paper design) and figure out what you did. That's how you'll learn."
Walker, who is self-taught, said he became interested in the Japanese art form when he was 7 years old. He saw a book on origami at the library and thought, "This is interesting, let me try this." He added that origami is very inexpensive because there are no costly tools or supplies to buy.
Walker has shown his work in the Brooklyn Museum and the Museum of American Folk Art in New York City. He has taught many classes on the art to all ages, but said that he prefers to teach children.
"They have no preconceived notions about space," he said. "You tell them to turn a square into a triangle and they do it. Adults have to analyze it."