They were practical solutions.

This practical, problem-centered approach to invention is neither more nor less valid than the laboratory-centered, theory-driven approach that produces the innovations we tend to celebrate most loudly.

It is simply a different approach, one that has been responsible for a very large proportion of the useful inventions in human history, and one that was available to Mary Kenner precisely because it required observation and thinking more than it required laboratory access or institutional support.

The Ashtray Patent and Safety Thinking