"Scriptology" — Ambigram script

   A hidden message.

An ambigram (from Latin: ambi both + gram letter) is a word or words that can be read in more than one direction. The word reads a different message when upside down or turn over to form an entirely new word. There are many types of ambigrams such as rotational ambigrams, reflective types and 3-dimensional ones. The flipscript or rotational ambigram in which a word or words when flipped in a horizontal or vertical way spells another message is discovered here. The optical illusion displays a hidden message in the sentences.

— Typography
— Book