SB 3.8.16

tasyāṁ sa cāmbho-ruha-karṇikāyām
 avasthito lokam apaśyamānaḥ
parikraman vyomni vivṛtta-netraś
 catvāri lebhe ’nudiśaṁ mukhāni
Synonyms: 
tasyām — in that; saḥ — Brahmā; ca — and; ambhaḥ — water; ruha-karṇikāyām — whorl of the lotus; avasthitaḥ — being situated; lokam — the world; apaśyamānaḥ — without being able to see; parikraman — circumambulating; vyomni — in space; vivṛtta-netraḥ — while moving the eyes; catvāri — four; lebhe — achieved; anudiśam — in terms of direction; mukhāni — heads.
Translation: 
Brahmā, born out of the lotus flower, could not see the world, although he was situated in the whorl. He therefore circumambulated all of space, and while moving his eyes in all directions he achieved four heads in terms of the four directions.