“In most cases the impossibility becomes apparent after viewing the figure for a few seconds however the initial impression of a 3D object remains even after it has been contradicted. There are also more subtle examples of impossible objects where the the impossibility does not become apparent spontaneously and it is necessary to consciously examine the geometry of the implied object to determine that it is impossible.” The bed in the advertisement is an impossible object, a theme perhaps not discussed in topology or other sciences until later. The very words “impossible object” are suggestive of meanings which might be illuminatingly applied in the description of an artist, as Apollinaire himself was rather an impossible object, at least after some meanings are unpacked (Picasso drew him masturbating among friends). Any work of art, as an aesthetic illusion, is an impossible object in a separate sense. So Duchamp calls attention to an impossible object, while Penrose opens themes Duchamp might well be credited with appreciating, albeit tacitly. The spelling of Apolinère in relation to Apollinaire is like Guilliame in relation to my name, William, otherwise Bill Wilson. So think about the same name differently spelled. Your themes now include art, visual perception, platonic ideal beds, and reach Escher and undecidability, as if Duchamp had said, “I am a liar,” and pointed toward the pictured bed, itself a visual lie… If a work of art is true to itself, it is false to the materials which convey it. Were Duchamp to have said, “I am a liar,” his statement would be true if it were false, but false if it were true: thus an impossible object. Jasper Johns did write “I am a liar” in some works of art which elaborate on Duchampian undecidable verbal and visual statements.”

(William S. Wilson, from a posting here on Apolinère Enameled).