One day, a rumor circulated that project scientists were going to be required to wear military uniforms, even in the technical areas. Feynman couldn't resist lampooning what he considered a pointless directive. First, he taught the scientists in his group to flip pencils from a table into their hands in one motion. When a colleague, Hans Bethe, came to Feynman's area to discuss a calculation, Feynman suggested that the scientists compute by hand. When Bethe agreed, Feynman turned to his group and, aping the manner and jargon of a tough drill instructor, barked: "All right, pencils, calculate!" In unison, each scientist's pencil flipped through the air. "Present pencils!" shouted Feynman with military pomp. "Integrate!" Bethe laughed, as did Feynman and his group.

It wasn't all fun and games, however. Feynman was a tough task master, as well as dynamic and original. If one of the scientists objected that a Feynman idea was too complex or bizarre, the young scientist (Feynman was only in his early 20s at the time) insisted that the team drop everything to test his thinking. Feynman's demanding nature, tempered by his sense of humor, inspired experimentation and innovation, and eventually won the loyalty of his team. It also earned him the respect of more senior scientists on site. Project director J. Robert Oppenheimer once called Feynman the Manhattan Project's most brilliant scientist.