Sublime

First, break the plane’s design into essential units and make a separate production layout for each unit. Next, build as many units as are required, then deliver each unit in its proper sequence to the assembly line to make one whole unit—a finished plane.

Resmelting of steel is by far the largest recycling effort in overall mass terms, an achievement made easier by the ubiquitous availability of the material, by the ease of its separation (magnetic sorting), and by its perfect recyclability: resmelted material retains all physical properties of the original metal.

Physically and chemically, these four materials are distinguished by an enormous diversity of properties and functions. But despite these differences in attributes and specific uses, they share more than their indispensability for the functioning of modern societies. They are needed in larger (and still increasing) quantities than are other