Alex Faickney Osborn, the “O” in BBDO (one of the largest global networks of advertising agencies), is the father of “thinking up.” We now call it “brainstorming” and like to complicate it, but in the way O conceived it, nearly 40 years before the Post-it note, there were just two principles at play:

• Defer judgment

• Reach for quantity

And four simple rules:

1. Go for quantity

2. Withhold criticism

3. Welcome wild ideas

4. Combine and improve ideas