YogSutras Of Patanjali: Sadhan Paad Yogsutra 18
Patanjali details the nature, form and purpose of drishya, Prakaashakriyaasthitisheelam bhootendriyaatmakam bhogaapavargaartham drishyam Prakaasha: Light (Satva) Kriyaa: Action (Rajas) Sthiti: Inertia (Tamas) Sheelam: Nature Bhoota: