Rongorongo -Hieroglyphs written with shark teeth from Easter Island, remain indecipherable
Unfortunately, there are faith heads who insist attributing these markings to intelligent agency. Classic hieroglyphics-of-the-gaps reasoning. Despite the proven track record of science to explain how things that give the appearance of having been designed for a purpose are, in fact, the product of non-purposive processes, faith heads, with their superstitious belief in skyhooks, refuse to wait for science to discover the natural cause of these random markings. Cryptography is a cop-out. A science stopper!