This is the outline of a pile of ten counting rods. It may have looked something like the image on the right. It is a unit of ten.
Illustrative Text Reference:
Chanhujo-daro: Copper object: C-40 A: Jagat Pati Joshi and Asko Parpola, 1987: Corpus of Indus Seals and Inscriptions: Volume 1: Page 338: Collections in India: Suomalainen Tiedeakatemia.
Comments:
This is Mahadevan's sign number 312, which I have redrawn to better reflect the original.
You should remember that this is a picture of ten counting rods. Therefore, when you have more than one unit of ten, the symbols are not nested.
Please note that Mahadevan's sign number 118 does not mean ten. It is two words, winter and night. There should be a small gap between the first six lines and the last four. In H-1088 A, the words were impressed onto a disposable cup. Perhaps they were the name of a beer.
Image Credits:
Indus Unit of Ten and Ten Counting Rods: Lynn Fawcett, 2018.
Indus Script Sign Number 118: Sign List of the Indus Script: Iravatham Mahadevan, 1977: The Indus Script: Texts, Concordance and Tables: The Director General Archaeological Survey of India.