Education: Plastic School

So changeable are U.S. communities that new schools can become obsolete tomorrow. Needed: buildings as portable as tepees, as stretchable as the mind. Last week the nearest thing to this ideal was announced by M.I.T.'s department of architecture—a plastic prefab school that can be erected on its foundation in a week, dismantled and reassembled elsewhere in about two.

The secret: a series of steel-and-plastic "tree units," which look like beach umbrellas with canopies curving upward instead of down. Bolted together, they form ceilings and roof; supporting pipe columns carry the load. By simply adding or subtracting tree units, the school can...