Support for Lesson 3 - Drawing in curved Spaces.
https://steemit.com/artzone/@javier.dejuan/curved-drawing-lessons-1-geometry-beyond-planar-perspective
https://steemit.com/artzone/@javier.dejuan/curved-drawing-lessons-2-the-spherical-geometry
https://steemit.com/utopian-io/@javier.dejuan/curved-drawing-lesson-3-deep-inside-the-equirectangular-grid