Great Logos with a Secret Meaning
I always admired the Northwest Airlines logo (much more than I ever admired the airline itself), with its very clever triple play inside the circle: the slanted N becomes part of a W for the initials of NorthWest, and the left tip of the W doubles as a compass arrow pointing to the northwest. Unfortunately, this logo disappeared along with the company name when Northwest Airlines merged with Delta.
This blog post at BuzzFeed shows off many other brilliant logos with hidden features.