Cahill-Keyes map projection (I modified Waterman butterfly projection in the geo.polyhedron D3 plugin to have incisions at 17° (Thanks Jason for the great inspiration!).
Gene Keyes's first 5 principles:
- principal format to an M-shape, joined at south Atlantic
- principal dividing meridian to 20° W
- incisions at equator and poles at 17°
- proportionality of geocells
- circular parallels for the polar regions