LEARNING BY DOING: (above, from left) Ryan Helt of Rochester, Ind. and Debra Voisin of Worthington, Ohio build a section of an what will become an elaborate working machine.
PLAYING WITH MARBLES: (above) a group of trainees stand behind their “Raising the Flag” machine, a Rube Goldberg-like contraption combining different devices all set into operation by a moving marble. The finale comes when the last device raises a small flag.