The HEALPix projection is a family of map projections, the members of which are distinguished by their H and K parameters that describe the specific arrangement. The H=4, K=3 HEALPix projection, as shown here applied to Earth, maps the sphere to twelve square facets (diamonds) on the plane, then divides these facets into pixels. This projection is widely used in physical cosmology for maps of the cosmic microwave background.Map: Strebe, using Geocart