The fuller map grid and land mass are based on:

  https://en.wikipedia.org/wiki/File:Fuller_projection_rotated.svg

which is licensed under the Creative Commons Attribution-Share Alike 2.5 Generic license (see https://creativecommons.org/licenses/by-sa/2.5/deed.en).
Attribution: Eric Gaba, Wikimedia Commons user Sting

The work has been modified and used by Anton Popov <mail@antonpopov.de>.
CC-BY-SA (see above)