The Indus Dictionary Project
This is the outline of a stylized horse. It is the noun horse or horses. The corresponding character in Chinese is mǎ 马. A key feature of the horse is its mane. The mane in this example is represented by the equivalent of the Chinese character shān 彡. In the Indus sign, shān 彡 has been rotated through around 90 degrees. If you look up the word 马 in Richard Sear's etymology, you will see many instances of 彡 incorporated into variants of the symbol for horse¹.
Mohenjo-daro: Seal: M-976 a: Sayid Ghulam Mustafa Shah and Asko Parpola, 1991: Corpus of Indus Seals and Inscriptions: Volume 2: Page 95: Collections in Pakistan: Suomalainen Tiedeakatemia.
This Indus pictograph appears to depict a stallion in a combat stance. His mane is flowing in the wind. The forelegs are straight and the hind legs are splayed out. The stallion would adopt this position prior to rearing back on his hind legs.
Indus Script Sign Number 1203: List of Sign Variants: Iravatham Mahadevan, 1977: The Indus Script: Texts, Concordance and Tables: The Director General Archaeological Survey of India.
1. Richard Sears: Chinese Etymology: http://www.chineseetymology.org/CharacterEtymology.aspx?submitButton1=Etymology&characterInput=%E9%A9%AC: Accessed: 24 February 2017.