Jason Vollen and Kelly Winn of the Rensselaer Polytechnic Institute created hollow, honeycomb shaped bricks that use small ridges on the outside to create "self-shading": the ridges ensure that, throughout the day, different parts of the brick absorb the sun's heat, while others cool. The air pockets inside the bricks can be sealed off, so that they serve as reservoirs of warm or cool air for winter and summer -- but they can also be left open, creating a beautiful open-brick wall with a latticework effect. These strategies are used in cactuses and termite mounds, too.
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