Andrea Liu and her lab have discovered new principles that allow them to easily design mechanical metamaterials. These include some with a negative Poisson ratio, which stretch in the horizontal direction when you stretch them vertically. (Most materials have a positive Poisson ratio, so that if you stretch them vertically they contract in the horizontal direction, like a rubber band). They are also working with systems that have even more complex responses inspired by biology, like allostery, which underlies nearly every biochemical process in our bodies. These ideas may lead to new strategies for robotics or drug design.