There is a book out there, written in modern times (1976-1978) of which we know not much about. We know that an Italian (artist, architect and an industrial engineer) by the name of Luigi Serafini decided to write a book that is 360 pages that has some strange diagrams and is written in a script, that no one has been able to decipher to day.
The books is called Codex Seraphinianus. Published in 1981, it is seems to be an encyclopedia of some imaginary world. Like the picture below of a couple copulating and morphing into an alligator.
Even the numerology that is used, was something that baffled people, until it was decoded. It is a variation of base 21.
The writing style is left-to-right writing. It has both UPPERCASE and lowercase letters. Some say its possibly a false writing system that has no meaning at all, but linguists are not so easily convinced. They believe it is of something of value.
However, most believe if the system had to be cracked it would have been, and they believe the writing is Asemic writing.
The entire book can be downloaded from here.