Trees are a perfect illustration of the butterfly effect, or chaos theory.
Stand back and look at a sycamore tree (for example)
and compare it with a couple of others.
The general shape and spread will be roughly the same.
closer at the tip of a twig
and follow it back as it twists and turns
joining ever larger limbs until you reach the trunk.
From sapling to maturity,
it is impossible to predict the precise location and path of your twig.
There are a multitude of unknown variables at work:
varying seasons from one year to the next,
each imperceptibly asserting a tiny influence
on the the tree’s overall plan.