Vaisesika Sūtra 4.1.08

अनेकद्रव्यसमवायाद् रूपविशेषाच्च रूपोपलब्धिः ॥८॥

anekadravyasamavāyād rūpaviśeṣāc ca rūpopalabdhiḥ ॥8॥

[अनेक-द्रव्य-समवायात् (aneka-dravya-samavāyāt) - due to conjunction of many substances; रूप-विशेषात् (rūpa-viśeṣāt) - due to distinctive form; च (ca) - and; रूप-उपलब्धिः (rūpa-upalabdhiḥ) - the act of acquiring form;]

The act of acquiring form and perception of form distinctively is due to conjunction of many substances.