Matsya Purana — Description of Gomedaka and Puṣkara Dvīpas; the Lokāloka Boundary; Ocean Tide...
प्रकाशश्चाप्रकाशश्च लोकालोकः स उच्यते आलोकस्तत्र चार्वाक्च निरालोकस्ततः परम् //
prakāśaścāprakāśaśca lokālokaḥ sa ucyate ālokastatra cārvākca nirālokastataḥ param //
That (cosmic boundary) is called Lokāloka, for it is both luminous and non-luminous. On this side there is light extending up to its limit, but beyond it there is utter absence of light.
It describes the cosmic structure of the universe: a boundary (Lokāloka) separating the illuminated, knowable world from the lightless expanse beyond—an important cosmographic framework often referenced when explaining cosmic cycles and the limits of manifested order.
Indirectly, it reinforces the Purāṇic worldview that dharma operates within the ordered, illumined realm (loka). Kings and householders uphold that order through righteous conduct, mirroring the boundary between order (light) and chaos (darkness).
No direct Vāstu or ritual rule is stated, but the idea of a sacred boundary between illumined and non-illumined space parallels temple planning concepts of ordered zones (prākāra/limits) separating consecrated space from the outer, unregulated realm.