Shunryu Suzuki uses a metaphor of waves and water to talk about “big mind, little mind” excerpt from Zen Mind, Beginner’s Mind:

(source: Traverse City Sangha:  http://tcmmg.org/big-mind-little-mind/ )

“That everything is included within your mind is the essence of mind. To experience this is to have a religious feeling. Even though waves arise, the essence of your mind is pure; it is just like clear water with a few waves.  .  .  . To speak of waves as apart from water or water apart from waves is a delusion. Water and waves are one. Big mind and small mind are one.  When you understand your mind in this way, you have some security in your feeling. As your mind does not expect anything from the outside, it is always filled. A mind with waves in it is not a disturbed mind, but actually a simplified one. Whatever you experience is an expression of big mind.”