And that's what I wrote. Buildings are not part of nature, it's man made. Hence it will mess up a 7D sometimes.
And what does it matter if it is nature or not, does it matter if it is West or East of Greenwich? A camera should be able to shoot A and B, whatever they may be, without introducing things that where not there... or it stops being a camera.
You don't even need patterns, just shoot sand, leaves, anything with lots of fine detail. It may be harder to notice than in a grid of equal frequency detail, but it is there.
Don't get me wrong, I love my 7D, but if we want to pretend they are video cameras, then we need to treat them as such. To be a video camera it needs a solution.