I just was thinking about the render window..when the thing starts to render, you can see the little squares..i presume that illustrates the bucket size...larger the bucket, fewer and larger squares. but my question...what determines the portion of the image that is shown on those little squares ??? I must be bored, but the thing is rendering now...need to do something :)

Humankind has not woven the web of life. We are but one thread within it.
Whatever we do to the web, we do to ourselves. All things are bound together.
All things connect......Chief Seattle, 1854