This is a pictograph of vertical shoring. The horizontal bar is designed to prevent lateral movement of the vertical props.
Sample Text Reference:
Mohenjo-daro: Seal: M-948 a: Sayid Ghulam Mustafa Shah and Asko Parpola, 1991: Corpus of Indus Seals and Inscriptions: Volume 2: Page 92: Collections in Pakistan: Suomalainen Tiedeakatemia.
A sealing made with M-948 may have been attached to a shipment of shoring timbers. Vertical shoring could have been used on some of the pack trails. Maintenance of the pack trails would have been
an important activity.
Indus Script Sign Number 2395: List of Sign Variants: Iravatham Mahadevan, 1977: The Indus Script: Texts, Concordance and Tables: The Director General Archaeological Survey of India.