The Indus Dictionary Project
This is a pictograph of a mat with each short edge split into six units. It therefore denotes a floor or pitch area with a size of six standard mats.
Mohenjo-daro: Seal: M-1103 a: Sayid Ghulam Mustafa Shah and Asko Parpola, 1991: Corpus of Indus Seals and Inscriptions: Volume 2: Page 116: Collections in Pakistan: Suomalainen Tiedeakatemia.
There is only one extant example of this Indus sign. The pitch would have been relatively large. Inscription M-1103 tells us that the pitch was used for oiling wheels. Hence, we can infer that the pitch was big enough to take at least one cart.
Indus Script Sign Number 1337: List of Sign Variants: Iravatham Mahadevan, 1977: The Indus Script: Texts, Concordance and Tables: The Director General Archaeological Survey of India.