fter the long and careful empirical study of inverted models hung with weights from chains or strings and of graphical calculations, Gaudí arrived at the revolutionary idea of leaning columns branching out like trees and of using the idea of a forest, not only as a space of magical lighting conducive to intimacy and meditation, but as an organised and hierarchical structure for the optimal support of a beautiful vault of leaves. Each tree splits into branches and supports part of the vaulting; when one tree falls, the whole forest does not collapse.