Spherical Perspective 

M.C. Escher is the most notable practitioner of Spherical Perspective, where no straight lines exist and everything is rendered as a curved line.  He used the form to create some wonderful and fantastic renderings.  Odd as it may appear, of all perspective forms, this is the one closest to the way your eyeball actually perceives the world.  The Central Vanishing Point is actually the Observation Point in this construction.  Since the Central Vanishing Point is at the centre of the sphere, viewing this as a coherent rendering is problematic indeed.  Unless of course, it is projected onto a curved surface; something like your retina, for example.  Any attempt to rationalize this into straight lines can lead to some bizarre results.  Which Escher was only too happy to exploit.

M.C. Escher; Hand with Reflecting Globe , collection of the Artist, reproduced in Escher; pl. 51

M.C. Escher; High and Low, collection of the Artist,
reproduced in M.C. Escher; The Graphic Work of M.C. Escher , New York, Ballantine, pl. 64