八識規矩補註 2.36

2.36

This says that the eighth, the manifest consciousness, is like water; the manifest activity and seeds of the eight consciousnesses are like waves; and the four conditions, such as cognitive objects, are like the wind. If the wind of the four conditions constantly strikes the manifest water of the eighth, then it constantly gives rise to the waves of the seeds and manifest activity of the eight consciousnesses. In the metaphor, when much wind arrives, many waves arise; when little wind arrives, few waves arise. In the doctrine, through many conditions many consciousnesses arise; through few conditions few consciousnesses arise. Thus the Laṅkāvatāra says, "Just as the ocean encountering a favourable wind," etc., as seen above.