The Indus script (also known as the Harappan script) is a corpus of symbols produced by the Indus Valley Civilisation during the Kot Diji and Mature Harappan periods between 3500 and 1900 BCE. Most inscriptions containing these symbols are extremely short, making it difficult to judge whether or not these symbols constituted a script used to record a language, or even symbolise a writing system.[4] In spite of many attempts,[5] ‘the script’ has not yet been deciphered, but efforts are ongoing. There is no known bilingual inscription to help decipher the script, and the script shows no significant changes over time.