 How does Purnie stop time?
When Purnie had stopped time, the bees—like all the other creatures he met—had been arrested in their native activities, and he knew that as soon as he resumed time, everything would pick up where it had left off. He chose to ignore the negative maxim that "small children who stop time without an adult being present, may not live to regret it." It was time itself that Purnie had stopped, not the world around him. The tripon thought Purnie's feat was superb. Purnie ran from pillar to post, trying to see and do everything at once. Purnie shrieked with joy at this new frolic and promptly stood on his head.
 Purnie stops time with his thoughts.
 Purnie stops time using tripons.  Purnie stops time by standing on his head.  Purnie stops time using radiation.  Purnie stops time with his thoughts.