In the symbols meaning to cut or split, the cutting tool is placed on the right, whereas in this symbol, the cutting tool is placed on the left. Hence, the action is reversed, so that things are
being brought together rather than separated. Therefore, this is an ideograph for the verb to put together or to combine.
Illustrative Text Reference:
Mohenjo-daro: Seal: M-309 a: Jagat Pati Joshi and Asko Parpola, 1987: Corpus of Indus Seals and Inscriptions: Volume 1: Page 77: Collections in India: Suomalainen Tiedeakatemia.