This is a pictograph of a human lower limb. The limb is facing towards the reader. Hence, the mirrored version of Mahadevan's sign number 49 is an ideograph for the verb to arrive.
Illustrative Text References:
Mohenjo-daro: Seal: M-226 a: Jagat Pati Joshi and Asko Parpola, 1987: Corpus of Indus Seals and Inscriptions: Volume 1: Page 57: Collections in India: Suomalainen Tiedeakatemia.
Mohenjo-daro: Seal: M-1690 a: Asko Parpola, B. M. Pande, and Petteri Koskikallio, 2010: Corpus of Indus Seals and Inscriptions: Volume 3,1: Page 17: New material, untraced objects, and collections outside India and Pakistan: Suomalainen Tiedeakatemia.
Comment:
There is the suggestion of a heel, which may indicate that the person is wearing some kind of footwear. Footwear would have been reserved for outdoor use.
Image Credit:
Indus Script Sign Number 49 (mirrored): Sign List of the Indus Script: Iravatham Mahadevan, 1977: The Indus Script: Texts, Concordance and Tables: The Director General Archaeological Survey of India.