Complex sentence: Christ, John's hand and the bird form an axle which divides the painting in two symmetrical parts, but this division is contradicted by the tree on the left, which instead divides it according to the golden ratio.
Split into simpler sentences: Christ, John's hand and the bird form an axis which divides the painting in two symmetrical parts. A second division is created by the tree on the left, which instead divides it according to the golden ratio.