The azimuthal equidistant projection is an azimuthal map projection. It has the useful properties that all points on the map are at proportionally correct distances from the center point, and that all points on the map are at the correct azimuth (direction) from the center point. A useful application for this type of projection is a polar projection which shows all meridians (lines of longitude) as straight, with distances from the pole represented correctly.
The flag of the United Nations contains an example of a polar azimuthal equidistant projection. The polar azimuthal equidistant projection has also been adopted by 21st century Flat Earthers as a map of the Flat Earth, particularly due to its use in the UN flag and its depiction of Antarctica as a ring around the edge of the Earth.
Azimuthal equidistant projection https://en.wikipedia.org/wiki/Azimuthal_equidistant_projection
But I would add that Flat Earthers don't exist.