At a recent assembly, students at Germantown Friends watched the director of the upper school play rock-paper-scissors with a robotic claw.

The school head won.

But perhaps more interesting is that three 10th graders built the claw in about six hours during a "Makerspace" class in January.

Two of the same students, Leo Kastenberg and Will Hagele, also crafted a computerized chess game, which took a lot longer — a whole semester.

"It looks at all the possible moves, and for every possible move, it sees all the possible reactions, and possible reactions it can make to that," Kastenberg, 15, said as a classmate tried to beat the game one day during class.

"I just lost," announced Coby Keren, 15.

Kastenberg and Hagele have emerged as computer whizzes at Germantown Friends School, a private, pre-K-12 Quaker school in Philadelphia, where annual tuition for grades 9 through 12 tops $37,000. The Makerspace class is part of the school's J-term, which takes place at the upper school during the month of January. All regular classes in core subjects like physics, chemistry, and English are canceled and teachers roll out a menu of creative classes that cross disciplines and explore passions and interests. The classes are meant to provide teachers and students with a place for "experimentation, investigation and reflection," according to the school's website.

In their fourth year, J-term classes are ungraded and cover a range of topics. This year there were classes on astronomy, documentary film history, alternative energy technology, meditation and yoga, Watergate, and "The Fourth Amendment: Police Officers and Your Rights." In a course called "Going to the Dogs," students explored "dogs from both a literary perspective — reading fiction and poetry about dogs, as well as writing about dogs — and from a working world perspective, learning about police dogs, rescue dogs, comfort dogs, service dogs."

Another focused on "Design Thinking: The Social Good Project." In another, students re-argued Supreme Court cases.

"It has a way of just sort of breathing life into the institution," said Carol Rawlings Miller, the school's director of academic program.

Kastenberg, Hagele, and classmate Jake Moss were excited to have a class where they could build their robotic claw.

Physics teacher John Henderson co-taught the Makerspace class at Germantown Friends School JESSICA GRIFFIN / Staff Photographer.
Jessica Griffin
Physics teacher John Henderson co-taught the Makerspace class at Germantown Friends School JESSICA GRIFFIN / Staff Photographer.

"I was not used to students coming to the first day of J-term class with projects they wanted to do," said John Henderson, who taught the class along with Nick Renner, a 2006 graduate of the school. "They brought supplies and sat down and got to work."

Renner, who also had Kastenberg and Hagele in an advanced programming class where they started making the chess game, said both students have produced a high volume of high-quality work, and building a chess game was quite a feat.

"It's a very complicated project," Renner said.

Students demonstrate how the claw plays rock, paper, scissors. JESSICA GRIFFIN / Staff Photographer.
Jessica Griffin
Students demonstrate how the claw plays rock, paper, scissors. JESSICA GRIFFIN / Staff Photographer.

Most of the work on the chess game was done outside of class on their own time.

"It still has some bugs," said Hagele, 15. "We're still optimizing it, so it's not as fast as it could be."

Kastenberg said he had to build a structure to teach the computer what chess is. He tried downloading one off the internet, but he didn't like it.

"I figured I could make one that was easier to use," he said.

That part alone took a couple of months. He had to program moves for each piece, create a way to move pieces and undo moves.

He's played the game a few times, and won only once.

Same for Hagele, who saw it as no defeat.

"You created it, and it beat you, so it's kind of like you beat you," Hagele said. "So you won."

Both students said they learned a lot.

"The experience was more about the process than what it actually does," Hagele said.

As for the rock-paper-scissors claw, the students wrote code, programmed it on a little board, and wired it. They initially planned to have the computer analyze an opponent's previous 10 moves and predict the next winning move. But they found that took too much time. So the board just triggers random moves or they can make the move for it.

Both Hagele and Kastenberg said they win about 50 percent of the time.

As for their motivation for attempting such projects, Kastenberg summed it up in two words: "It's fun."

Hagele's mother, Catherine, who was at the assembly where the rock-paper-scissors claw made its public debut, was amazed.

"I was just really proud and really grateful that he goes to a school where science is celebrated," she said, 'where creativity outside the classroom is encouraged."