- D. Engwirda, 2017: JIGSAW-GEO (1.0): Locally orthogonal staggered unstructured grid generation for general circulation modelling on the sphere, Geosci. Model Dev., 10, 2117-2140, doi:10.5194/gmd-10-2117-2017
and a general description at NASA. The figure below is copied from there.
Having worked with finite elements in the past, I find this grid generator very beautiful.