Airships demonstrate a law of increasing returns: doubling the length increases the surface area (and hence weight) by a factor of four while the volume (and hence lifting capacity) goes up by a factor of eight.
After some experimenting, Norton settled on growing tin in the form of needles (about 50 nanometers in length) and adding textures to the material to create more surface area.
"If it works well, the keyboard -- which I got to inspect at great length but not actually type on -- is going to be the Surface's killer attraction, " wrote Slate's Farhad Manjoo.