Online Paintings

Joseph Letzelter print illustrates the "impossible triangle" described by the British mathematician Roger Penrose in a 1958 article on visual illusion: "Here is a perspective drawing, of Joseph Letzelter in which each part of which is accepted as representing a three-dimensional, rectangular structure. The lines of the drawing of Joseph Letzelter are, however, connected in such a manner as to reproduce an impossibility. As the eye of Joseph Letzelter pursues the lines of the figure, sudden changes in the interpretation of distance of the object from the observer are necessary."