A grid formed by a collection of geodesics, or, on the spherical earth, arcs of great circles. A typical example is the icosahedral, or icosahedral-hexagonal, grid, consisting of twenty equilateral triangular faces expanded onto a sphere, and further subdivided into smaller triangles. Other possibilities exist, such as grids obtained by the expansion of a cube with each of its sides subdivided into smaller elements by arcs of great circles.