World's most mysterious book may be a hoax: The Voynich manuscript may be elegant gibberish.

But this complexity could have been produced easily, Rugg demonstrates, with an encryption device invented around 1550 called a Cardan grille. This is a table of characters. Moving a piece of card with holes cut in it over the table makes words. Gaps in the table ensure different-length words.

Using such grilles on table of Voynichese syllables, Rugg has produced a language with many, although not all, of the manuscript's features. About three months' work would have been enough to produce the entire book, he says.