THE MATERIAL ENGINES
Material as behavior under pressure, use, fracture, refinement, transparency, and endurance.
Members
Subgroups
THE TWIN TRANSPARENCIES
DIAMOND and GLASS are grouped as the Twin Transparencies.
Both are clear.
Neither is simple.
DIAMOND is transparency under pressure: hard, brilliant, compressed, and verdict-like.
GLASS is transparency under passage: fragile, revealing, refracting, and dangerous precisely because light can move through it.
They are not opposites.
They are the same demand for visibility under different material laws.