With a single drop of water, a sheet of silicon nitrate will fold into a cube, pyramid, bowl, or long triangular shape. The process to create the cool self-assembling structures isn’t that complicated, Discovery News reports. Similar to how kids cut out patterns from paper and fold along the dotted lines, scientists etch away at where they want the material to bend. An added droplet of water causes the silicon to react and pull together—leading to the desired form. The catch is that the folded shapes, described this week in the Journal of Applied Physics, are no bigger than a grain of sand.