About 500 years ago the Japanese poet Basho wrote a haiku that can be translated roughly as:
Frog jump in
One of the many possible interpretations of this poem is that the old pond is our awareness and the frog represents anything moving in our awareness – thoughts, imaginings, emotions, appetites. So we imagine a completely still pond, and a single frog jumping in; we imagine a completely still mind, and a single thought moving through it.
Most of the time, though, our mind is full of ploop. Frogs leaping everywhere. How do we quiet these frightened, horny frogs? How do we calm our awareness? How do we get to that old pond, our original mind?