Matsya Purana — Mandāra-Saptamī Vrata
कर्णिकायां च पुरुषं सर्वात्मन इति न्यसेत् शुक्लवस्त्रैः समावेष्ट्य भक्ष्यैर्माल्यफलादिभिः //
karṇikāyāṃ ca puruṣaṃ sarvātmana iti nyaset śuklavastraiḥ samāveṣṭya bhakṣyairmālyaphalādibhiḥ //
In the central lotus (the core of the maṇḍala), one should install by nyāsa the Vāstu-Puruṣa with the mantra “sarvātmanaḥ” (“the One who is the Self of all”). Having wrapped (the seat) with white cloth, one should offer edibles, garlands, fruits, and the like.
This verse is not about pralaya; it teaches a Vāstu ritual: installing the Vāstu-Puruṣa in the mandala’s center as the “All-Self,” indicating a metaphysical grounding of space rather than a flood or dissolution narrative.
It frames proper building and consecration as a dharmic duty: a householder or king should sanctify a site by nyāsa and pure offerings (white cloth, food, garlands, fruits) to ensure the dwelling/temple aligns with cosmic order.
Architecturally, it identifies the karṇikā (central point) of the Vāstu mandala as the key locus; ritually, it prescribes nyāsa of Vāstu-Puruṣa with the epithet “sarvātmanaḥ” and standard auspicious offerings.