Tree of Life
The Tree of Life alludes to the inter connectedness of all life on our planet and serves as a metaphor for common decent in the evolutionary sense invoking a balance in the cycle of life.
The perfect balance
Physical illustrations of balance (equal air pressure) on the inside as well as the outside.
A self-similar object is exactly or approximately similar to a part of itself i.e. the whole has the same / similar shape as one or more of the parts.
Self Similarity in Nature
Because no element can be coerced to follow a certain path, no large number of elements in nature will display the exact same pattern as another group. Patterns caused by large numbers of elements are alike but never the same.