The Handbook of Magazine Article Writing contains this illustration by Philip Barry Osborne;

“Alex Haley, the author of ROOTS, has a picture in his office, showing a turtle sitting atop a fence. The picture is there to remind him of a lesson he learned long ago: ‘If you see a turtle on a fence post, you know he had some help.’

“Says Alex, ‘Any time I start thinking, WOW, isn’t this marvelous what I’ve done! I look at that picture and remember how this turtle—me—got up on that post.’“

Handbook of Magazine Article Writing