But these lithographic approaches begin to break down when you try to fabricate even seemingly simple 3-D objects, which is what you need for a metamaterial that can act on light regardless of direction. Lithography is designed to pattern 2-D features, so to construct an array or tiny helical coils, for example, you’d have to construct them layer by layer in hundreds of steps. It’s a time-consuming process that requires careful alignment. Even research groups that are adept at the process might need an entire day to make a single layer.