This is a pictograph of a mat with each short edge split into four units. It therefore denotes a floor or pitch area with a width of four standard mats.
Illustrative Text Reference:
Chanhu-daro: Seal: C-32 a: Jagat Pati Joshi and Asko Parpola, 1987: Corpus of Indus Seals and Inscriptions: Volume 1: Page 335: Collections in India: Suomalainen Tiedeakatemia.
Image Credit:
Indus Script Sign Number 1038 (Pitch 4 wide): List of Sign Variants: Iravatham Mahadevan, 1977: The Indus Script: Texts, Concordance and Tables: The Director General Archaeological Survey of India.