The Necker cube is an optical illusion that was first published as a rhomboid in 1832 by Swiss crystallographer Louis Albert Necker. It is a simple, wire-frame, two-dimensional drawing of a translucen
Ancient Roman mosaic
An ambigram is a calligraphic composition of glyphs that can yield different meanings depending on the orientation of observation. Most ambigrams are visual palindromes that rely on some kind of symme
Necker cube
…push-and-pull of a Necker cube. "[B]y dividing it into signifier and signified," Kirbach writes, "we might say that Saussure himself 'neckerized' the sign". Ambigram Binocular rivalry…
Sator square (word square and palindrome) with the letters S and N in mirror writing.
Rotational ambigram Puzzle / The end by Peter Newell designed in 1893.
Mirror ambigram ΝΙΨΟΝ ΑΝΟΜΗΜΑΤΑ ΜΗ ΜΟΝΑΝ ΟΨΙΝ (Wash your sins, not only your face, in Ancient Greek) in the monastery Panagia Malevi [el].
Ambigrams published in The Strand Magazine, June 1908.