Audie Cornish and Robert Siegel have a remembrance of Andre Cassagnes, the inventor of the Etch A Sketch. Cassagnes died Jan. 16 at the age of 86. And I'm Audie Cornish. We're going to take a moment ...

"The goal of any design is to be simple, elegant and robust," Paley states early in his passionate first book, and this guiding principle runs throughout his examination of the process of invention.