What is an Organising Idea?

If you've read any of Henri Bortoft's books such as The Wholeness of Nature (or ever been a student of Stuart Hill, for that matter) you will have seen this picture before. It was created by Jackie Bortoft to illustrate the proactive nature of perception and the concept of the organising idea.  I'm using it here with permission from Henri and Jackie Bortoft.

Once you have seen the animal's head in the picture its shape seems quite obvious, but if you can't see it, it's as if it's not there. Your perception changes, but the marks on the page have not changed.

There is more about this in my Seven Aspects of Knowing, under PERCEPTION.

Also, some well-known ambiguous figures to think about, if you want to.