Sometimes you might choose to go the long way round because there was somewhere that you wanted to visit on the way. This is a pictograph of a circuitous route, with the destination point marked on it.
You should note that the destination point is in effect a point of light. It might be likened to placing the point of interest under a spot light.
Hence, Mahadevan's sign number 320 is the phrasal verb: to make a detour to.
Illustrative Text Reference:
Lothal: Seal: L-26 a: Jagat Pati Joshi and Asko Parpola, 1987: Corpus of Indus Seals and Inscriptions: Volume 1: Page 244: Collections in India: Suomalainen Tiedeakatemia.
Comment:
There is only one extant example of this Indus sign.
Image Credit:
Indus Script Sign Number 320: Sign List of the Indus Script: Iravatham Mahadevan, 1977: The Indus Script: Texts, Concordance and Tables: The Director General Archaeological Survey of India.