The crazy-huge mountains of the nanoworld! The strange waves and scallops are what is left of the protective mask I used to shield the semiconductor material below from a high-energy etching plasma. The mask held up to the plasma, although it was probably damaged a bit - and then I damaged it further by a couple of rounds in another plasma, that we use to get rid of polymer buildup. This is what the sample looked like under the microscope after the last plasma cleaning step - fluffy mountains made of thick residual mask. I didn’t care about the fate of the mask - all I cared was that it had done its job, and that I could tell that the etch worked on the unprotected bits of semiconductor. It did work, as evidenced by the sharp cliff. Acetone later washed the mask away, leaving the upper surface of the cliff smooth and clean.