In this pictograph of a bird, the wing position, with the downward facing wingtips, suggests take off. Hence, this Indus sign is the phrasal verb to take off, or to leave the ground.
Illustrative Text Reference:
Mohenjo-daro: Seal: M-222 a: Jagat Pati Joshi and Asko Parpola, 1987: Corpus of Indus Seals and Inscriptions: Volume 1: Page 56: Collections in India: Suomalainen Tiedeakatemia.
Image Credit:
To Take Off: Lynn Fawcett, 2018.