The Indus script has several symbols built around the sign on the left. They all relate to the different ways in which we use our hands and arms.
For image credits, please see below.
Indus Script Signs with Numbers: Sign List of the Indus Script and List of Sign Variants: Iravatham Mahadevan, 1977: The Indus Script: Texts, Concordance and Tables: The Director General
Archaeological Survey of India.
Indus Script Signs without Numbers: Lynn Fawcett, 2017 - 2019.