This motif is a diagram of a citadel. The format conforms to the normal Indus style for diagrams depicting built structures. It is a diamond shape, and although the diagram is symmetrical, we know that by convention, the direction north-west is placed at the top of the diagram. There is an outer enclosure, which represents the perimeter wall of the city. Within the outer enclosure is a further barrier comprised of four towers with curtain walls between them. Within the curtain walls, there is another structure marked with the Indus sign meaning obscure, which can also be translated as the verb to hide.
Illustrative Motif Reference:
Mohenjo-daro: Seal: M-1255 a: Sayid Ghulam Mustafa Shah and Asko Parpola, 1991: Corpus of Indus Seals and Inscriptions: Volume 2: Page 158: Collections in Pakistan: Suomalainen Tiedeakatemia.
Comment:
Excavations at Mohenjo-daro found evidence of towers at the south-eastern corner of the citadel¹. Therefore, it seems likely that the motif portrays the design of the actual citadel.
Image Credit:
Citadel: Lynn Fawcett, 2017.
Note:
1. Mortimer Wheeler, 1950: Images from Sir Mortimer Wheeler's Personal Collection: Harappa.com: https://www.harappa.com/slide/group-towers-south-eastern-corner-citadel-mohenjo-daro-117: Accessed: 10 May 2020.