MIT engineers have developed a new elastic material coated with microscopic, hair-like structures that tilt in response to a magnetic field. Depending on the field's orientation, the nickel microhairs can tilt to form a path through which fluid can flow. The material can even direct water upward, against gravity. Each microhair is about one-fourth the diameter of a human hair. The researchers fabricated an array of the microhairs onto an elastic, transparent layer of silicone. In experiments, the magnetically activated material directed the flow of light much as window blinds tilt to filter the sun. Researchers say the work could lead to waterproofing and anti-glare applications, such as smart windows for buildings and cars.