A rhizome has no beginning or end; it is always in the middle, between things, interbeing, intermezzo. The tree is filiation, but the rhizome is alliance, uniquely alliance. The tree imposes the verb 'to be', but the fabric of the rhizome is conjunction, 'and. . . and. . . and. . . '...The middle is by no means an average; on the contrary, it is where things pick up speed.

—Deleuze & Guattari, A Thousand Plateaus