There's an interesting/nerdy story about the design-evolution of the wheels on NASA's Curiosity Rover. The tale goes something like this...
An early suspension-test prototype rover was equipped with metal wheels which prominently featured "JPL" in raised letters which would imprint the company's initials onto the surface of Mars:
According to one of the scientists on the project, NASA was extremely upset by the "JPL" raised letters on the wheels, wanting them to read "NASA" instead. JPL assured NASA that this was merely a prototype and that the letters wouldn't appear on the final model.
Eventually the design was finalised and approved, and the wheels were made and fitted:
I'd imagine that the NASA folks would have felt that they'd won a little victory over JPL - all of the lettering on the wheels had been designed-out.
And I'd imagine that JPL's lot would have felt far more victorious because they'd got their initials in there anyway in the form of Morse Code which NASA, apparently, didn't notice:
Well, they launched Curiosity back in November 2011 and it's scheduled to land on Mars in August 2012 so there's no chance that they'll call it into the pits for a tyre-change. JPL will leave its mark on Mars despite NASA's objection. And those marks will be useful - the regular Morse patterns in the wheel-tracks will act as index marks, Curiosity's camera will count them to judge the distance travelled across the surface.
I reckon that's a cool story.
Of course you don't want to read too much into these things or you might start to believe that this pattern:
bears some similarity to this logo: