"I grew up wanting to fly," says Graham Bowen-Davies. "I guess I just settled for being an engineer."
He's standing on an indoor track in southern Maryland, watching a giant helicopter take flight. At the end of each of its four spindly arms — arms he helped design and build — a giant rotor churns the air. In the cockpit sits the engine: a 0.7-horsepower, 135-pound graduate student named Kyle Gluesenkamp.
Gluesenkamp is pedaling like crazy to keep the rotors spinning and the craft aloft.
On-air challenge: Every answer is a two-word phrase in which the letter "O" is added at the end of the first word to make the second word. For example, given the clue "pack animal owned by Thomas Jefferson's first vice president," the answer would be "Burr burro."
Last week's challenge: Draw a regular hexagon and connect every pair of vertices except one. The pair you don't connect are not on opposite sides of the hexagon but along a shorter diagonal. How many triangles of any size are in this figure?