Mahadevan's sign number 172 is made up of two opposing standards. Hence, it is an ideograph for the noun competition.
Illustrative Text Reference:
Kalibangan: Tablet in bas-relief: K-69 A: Jagat Pati Joshi and Asko Parpola, 1987: Corpus of Indus Seals and Inscriptions: Volume 1: Page 312: Collections in India: Suomalainen Tiedeakatemia.
Tablet K-69 may have been a token, which allowed entry to a tournament. The addition of a sloping line underneath the verb to follow in inscription K-69, suggests that the spectator would have
had a prime position on a slope.
Indus Script Sign Number 172: Sign List of the Indus Script: Iravatham Mahadevan, 1977: The Indus Script: Texts, Concordance and Tables: The Director General Archaeological Survey of India.