If you do not see the arrow in the FedEx logo before, now you will never be able to razvidet it. Just as work-designed logos - they play with the audience, reveal more to those who are able to see more, and contain as much information about the brand, as needed.
And it's really fun - just look into the details of the authors and admire wit and ability to invest more in low.
In this article Website has collected the best examples of smart and concise logos. For their creation just want to go and kiss the designers.