This silhouette of a tree pained on weathered fence board is from the giant oak trees of southern Louisiana where limbs touch the ground and children run up them.  I climbed these and was convinced that the roots connected to those limbs.  Later in life, I used the same image to explain interconnectedness, where all knowledge relates at the tips of branches.  In both ideas there's a reliance on metaphorical expression through nature to reduce complexity.    

“Nature, as a rich taxonomy of species and forms, provide a vast metaphorical tapestry for the creation of diverse and complex differentiations.”

(The Biophilia Hypothesis, Kellert & Wilson, 1993).