This poem comes from Autumn Leaves:

Betwixt and between,

Not here, nor there;

Betwixt and between

Existing somewhere.

Omniscient, invisible and

Transparent it seems,

Clinging ever so tenaciously,

Betwixt and between.

Although it can’t be touched,

Nor tasted nor seen,

Doesn’t mean it’s not there,

Betwixt and between.

Search the universe diligently

For mysteries so keen;

Efforts might be rewarded by

A fleeting glimpse of betwixt and between.