In traditional sericulture, when a silk moth is ready to spin its cocoon, it is given a twig to climb. This is a stylised pictograph of two cocoons suspended from a twig. Therefore, it is the compound noun silk cocoons.
Illustrative Text Reference:
Harappa: Tablet in bas-relief: H-1943 A: Asko Parpola, B. M. Pande, and Petteri Koskikallio, 2010: Corpus of Indus Seals and Inscriptions: Volume 3,1: Page 266: New material, untraced objects, and collections outside India and Pakistan: Suomalainen Tiedeakatemia.
Image Credit:
Indus Script Sign Number 1126: List of Sign Variants: Iravatham Mahadevan, 1977: The Indus Script: Texts, Concordance and Tables: The Director General Archaeological Survey of India.