Looking for the ultimate in natural daylight control? Do you think the ultimate is automatic window shade controls? There's something new that's growing fast. It's slick and simple and called ?smart glass.? It's window panes that go from clear to black -- with the flip of a switch. And, the panes can achieve virtually any shade of gray in between -- depending upon how much power you give it. The secret lies in millions of microscopic particles suspended between two panes of glass. With no power, the particles lie horizontally, allowing full light to pass through. But as power is increased, they become vertical, until they line up to block all light (under full power). Smart glass, with suspended particle devices, is still an emerging technology. Whereas it is available, it's expensive -- costing from $80 to $160 per square foot.