David K Gibson wrote about a surprisingly anachronistic practice in automobile design:

• Before car designs are approved they are first modelled with clay.
• Clay has the advantage of allowing iterations – the design can be added to, removed from, or changed around at will.
• It’s also collaborative. Multiple individuals can stand around and work on it.
• Each car company has its own proprietary blend of “clay” that it uses to make car designs.
• Ford, to take one example, goes through 100 tons of the material a year.

Read more about the process of car design, and find out what happens to the clay models on BBC.