Unlike the cuneiform inscriptions, Urartian hieroglyphic have not been successfully deciphered. These coded clues can be deciphered by using the Adventurer's Journal, included with the game. The inscriptions had not been deciphered, and proposed interpretations have been controversial. Indian archaeologist Shikaripura Ranganatha Rao claimed to have deciphered the Indus script. Archaeologists have deciphered over 15 pre-Columbian distinct writing systems from mesoamerican societies. No texts in Linear A have been deciphered. The main sculpture contains four separate enigmatic messages, three of which have been deciphered. The Etruscan civilization has been studied, and the language partly deciphered. The Navajo code is the only spoken military code never to have been deciphered. Indus script is largely pictorial and has not been deciphered yet. The Harrapans spoke an unknown language and their script has not yet been deciphered. False writing cannot be deciphered because it has no semantic meaning. The text was deciphered by graduate student Takayoshi Oshima working under professor Wayne Horowitz. Colossus, the world's first electronic digital computer, deciphered Tunny messages in quantity from 1943 onwards. The amount of text potentially to be deciphered by this technique is huge.