The ability to change a surface's profile allows biological systems to effectively manipulate and blend into their surroundings. Current surface morphing techniques rely either on having a small number of fixed states or on directly driving the entire system. We discovered a subset of scale-independent auxetic metamaterials have a state trajectory with a star-graph structure. At the central node, small nudges can move the material between trajectories, allowing us to locally shift Poisson's ratio, causing the material to take on different shapes under loading. While the number of possible shapes grows exponentially with the size of the material, the probability of finding one at random is vanishingly small. By actively guiding the material through the node points, we produce a reprogrammable surface that does not require inputs to maintain shape and can display arbitrary 2D information and take on complex 3D shapes. Our work opens new opportunities in micro devices, tactile displays, manufacturing, and robotic systems.

翻译：改变表面剖面的能力使生物系统能够有效地操纵和融入周围环境。 目前的表面变形技术依赖于拥有少量固定状态或直接驱动整个系统。 我们发现了一组具有星光结构的、 比例独立的辅助元材料。 在中央节点, 小缩略图可以在轨迹之间移动材料, 允许我们本地移动 Poisson 的比例, 导致材料以不同形状进入正在装入的状态。 虽然可能形状的数量随着材料的大小而成倍增长, 随机找到的概率很小。 通过通过节点积极引导材料, 我们产生一个不需要输入来维持形状的可重新编程的表面, 可以显示任意的 2D 信息, 并获取复杂的 3D 形状。 我们的工作在微小设备、 触摸显示、 制造和 机器人系统中开辟了新的机会 。