The first hole made through a piece of stone is a revelation. The hole connects one side to the other, making it immediately more three-dimensional. A hole can itself have as much shape-meaning as a solid mass. Sculpture in air is possible, where the stone contains only the hole, which is the intended and considered form. The mystery of the hole – the mysterious fascination of caves in hill sides and cliffs.

p. 251 - The sculptor speaks (1937)