Mahadevan's sign number 223 takes the basic pictograph of the upper torso and arms and adds mirrored signs. The mirrored signs form a pair. Hence, it is the phrase a pair of hands.
Illustrative Text References:
Mohenjo-daro: Seal: M-628 a: Sayid Ghulam Mustafa Shah and Asko Parpola, 1991: Corpus of Indus Seals and Inscriptions: Volume 2: Page 11: Collections in Pakistan: Suomalainen Tiedeakatemia.
Harappa: Tablet incised: H-952 A: Sayid Ghulam Mustafa Shah and Asko Parpola, 1991: Corpus of Indus Seals and Inscriptions: Volume 2: Page 341: Collections in Pakistan: Suomalainen Tiedeakatemia.
Image Credit:
Indus Script Sign Number 223: Sign List of the Indus Script: Iravatham Mahadevan, 1977: The Indus Script: Texts, Concordance and Tables: The Director General Archaeological Survey of India.