High-energy carbon atoms can be deposited onto a substrate to form a hard
diamondlike coating that can provide wear resistance in applications
ranging from hard drive to hip joints. Despite the energetic conditions of
their formation, these films are extremely smooth--the roughness can be as
low as 0.1 nanometers on a lateral area of 1 square micrometer (equivalent
of millimeter-scale bumps on a soccer field).

It's cool seeing all that stuff from near-future RPGs come true