The Mukhya Upaniṣads

Aitareya · Adhyāya 1 · Khaṇḍa 3 · The Search for Food, and the Discovery of Who Asks

Passage 12

स एतमेव सीमानं विदार्यैतया द्वारा प्रापद्यत ।सैषा विदृतिर्नाम द्वास्तदेतन्नान्दनं तस्य त्रय आवसथास्त्रयः स्वप्ना अयमावसथोऽयमावसथोऽयमावसथ इति ॥ १२ ॥

In plain words

He entered by splitting open this very boundary [the crown of the head], through this door. This is called the 'vidṛti' door. This is his delight (nāndana). Of him there are three dwellings, three dream-states: 'this is a dwelling, this is a dwelling, this is a dwelling,' thus.