The Trouble With Angels (1966)

"... the curve of a tree trunk, a muscle or a column, will display the essence of its form--for the tree, sap, for the muscle, blood, and for the column, an inner cohesive core providing structural integrity. Therefore, a convex wall will be characterized not only by an outward expansion but also by an inward-looking characterization."

"The Convex Wall," Archetypes in Architecture, Thomas Thiis-Evensen