Impossible cube ambiguity present in a Necker cube illustration, in which a cube is drawn with its edges as line segments, and can be interpreted as being in either of two different three-dimensional orientations. An impossible cube is usually rendered as a Necker cube in which the line segments representing the edges have been replaced by what are apparently solid beams. In Escher's print, the top four joints of the cube, and the upper of the two crossings between its beams, match one of the two interpretations of the Necker cube, while the bottom four joints and the bottom crossing match the
The Carnelian Cube The Carnelian Cube The Carnelian Cube is a fantasy novel by American writers L. Sprague de Camp and Fletcher Pratt. It was first published in hardcover by Gnome Press in 1948, and in paperback by Lancer Books in 1967. An E-book edition was published by Gollancz's SF Gateway imprint on September 29, 2011 as part of a general release of de Camp's works in electronic form. It has also been translated into Italian and German. The carnelian cube of the title is a small red "dream stone" confiscated by archaeologist Arthur Cleveland Finch from Tiridat Ariminian, one of the workers