The onion is one of Dave's best known images. He uses the illustration of an onion to present some of his most powerful concepts. Years after a presentation, people say to him, "I'm still peeling the onion".

It's also an example of one of the characteristics of Dave's presentations - he often uses simple, easy-to-understand and easy-to-remember visual images to illustrate his key points. This helps people learn, and provides them an image they can remember and use for years.

To find out exactly what the onion means, you'll need to attend one of his programs!