 Often, written captions are enclosed in square 'boxes' of various shapes within the representation.Wall paintings may also entirely consist of texts (Ek' Balam, Naj Tunich), or, more rarely, contain astrological computations (Xultun); sometimes, written on a white stuccoed surface, and executed with particular care and elegance, these texts are like enlargements of book pages.Hieroglyphs are ubiquitous and were written on every available surface, including the human body.