Argentine-born American architect Cesar Pelli views this expressive function of the skin as a signifier that changes across architectural periods and cultures.

"Most of the great and beautiful buildings of Western architecture were built of carved, load-bearing masonry," says Pelli. "Their forms contain most of our architectural memories. They still give shape to our cities.

"Yet the technology that gave them life is now obsolete. Today we have a new construction system with which to make architecture. As always, our only option is to understand the possibilities of the technologies available to us. It is our task to develop, with our technology, an architecture as rich, meaningful, and loved as was the architecture of stone."

New Technology, New Expression

Pelli asserts that load-bearing stone ceased to be a reasonable construction alternative by the mid-20th century. However, he says, "The aesthetic qualities of this system are so ingrained in our culture, that it has been difficult to adjust to their loss, and we have seen many efforts to recreate the old cherished forms in other materials, such as plastic casts, and thin stone veneers on hollow walls."

Unfortunately, without a direct connection to the underlying technology, all these efforts remain fruitless, Pelli believes. Form-giving needs to continuously test itself against the possibilities of construction or it degenerates.

"And the forms given, to have life, need to reflect an underlying physical reality. Architecture can grow only if it is rooted in a living tradition of building construction."