For example, when you sail out in a boat to the middle of an ocean where no land is in sight, and view the four directions, the ocean looks circular, and does not look any other way. But the ocean is neither round nor square; its features are infinite in variety. It is like a palace. It is like a jewel. It only looks circular as far as you can see at that time. All things are like this.
Though there are many features in the the dusty world and the world beyond conditions, you see and understand only what your eye of practice can reach. In order to learn the nature of the myriad things, you must know that although they may look round or square, the other features of oceans and mountains are infinite in variety; whole worlds are there. It is so not only around you, but also directly beneath your feet, or in a drop of water.
-Dogen Zenji, “Actualizing the Fundamental Point,” translated by Robert Aitken and Kazuaki Tanahashi, in Moon in a Dewdrop: Writings of Zen Master Dogen