One way of focusing intense beams of x-rays down to individual nanometers involves bending them through the stacks of atomically thin materials inside multilayer Laue lenses (MLL). These drop-like domes were carved through a process called reactive ion etching, which produced the striped bubbles in this false-colored electron microscope capture. Each dark line signified a marker layer built into these ultra precise lenses. This flawed prototype (the final lenses actually look much more like symmetrical towers) helped scientists perfect the synthesis process and prepare lenses to focus x-rays to within a single nanometer using instruments like Brookhaven's forthcoming National Synchrotron Light Source II.