@chjara your grids are going to be probably given by charts, and off the top of my head there’s three charts for a sphere:
@chjara That's what DGGS is for. https://en.wikipedia.org/wiki/Discrete_global_grid#Standard_equal-area_hierarchical_grids (via @alcinnz)
@chjara <Nim> stretched cube if you need squares specifically, otherwise icosohedron (grid of triangles, or hexagons with 12 pentagons)
@chjara there is not, at least in euclidean space and without non-uniform tilings
this isn’t a sphere, strictly speaking, but in hyperbolic space you could have an infinite square grid on the surface of a horosphere
@chjara technically a horosphere can be thought of as embedding a euclidean plane into hyperbolic space, but due to the nature of hyperbolic geometry, it looks curved like a ball.
it also exhibits horocyclic properties (a horocycle is to 2D as a horosphere is to 3D) like every point on its surface being tangent to an ideal point