This site also explains why the logos are special. I claim no ownership of this idea, but am happy to share their collection of images that I know your kids will find fascinating. In the Fed Ex logo, there is an arrow in the ground of the Ex figure.
In this next image, the Big Ten created an "11" in the ground when they added Penn State. I've looked at that logo all my life and never noticed it. Hmmmmmmm
Posted by Chuck Schallhorn