Bhagavad Gita 6.11

शुचौ देशे प्रतिष्ठाप्य स्थिरमासनमात्मनः।नात्युच्छ्रितं नातिनीचं चैलाजिनकुशोत्तरम्॥

śucau deśe pratiṣṭhāpya sthiramāsanamātmanaḥ |nātyucchritaṃ nātinīcaṃ cailājinakuśottaram ||

In a clean spot, having established a firm seat of his own, neither too high nor too low, made of cloth, skin, and kusha grass layered one over the other.

Having chosen a holy place, let him sit in a firm posture on a seat that is neither too high nor too low, and cover it with a grass mat, a deer skin, and a cloth.

Our plain-language meaning of this verse is waiting for scholar review.