When the sentence is rendered in capital letters, as would be usual for an inscription (ΝΙΨΟΝΑΝΟΜΗΜΑΤΑΜΗΜΟΝΑΝΟΨΙΝ), all the letters are vertically symmetrical except for the Ν. As a result, if the N is stylized Ͷ in the right half (ΝΙΨΟΝΑΝΟΜΗΜΑΤΑΜΗΜΟͶΑͶΟΨΙͶ), the sentence is not only a palindrome but also a mirror ambigram.
The romanization is not a palindrome because the Greek letter ψ (psi) is transcribed by the digraphps. The modern diacritics, which are not symmetrical, are usually omitted from inscriptions of the sentence.
Preminger, Alex; Brogan, Terry V.F.; Warnke, Frank J. (1993). The New Princeton Encyclopedia of Poetry and Poetics (3rded.). Princeton University Press. p.874. ISBN0-691-02123-6.