While psyching myself up for DrupalCon Boston 2008 I was browsing downtown Boston in google maps, I found this weird occurance of an accidental 'impossible picture':

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If you can't see what's odd about this, take a closer look here;

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and here;

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It's quite understandable how this can happen; three images converge and overlap at this point. The images were taken at a relatively low altitude. The amazing thing is there is no obvious merge point. I couldn't find any image-edges anywhere. Even more impressive is that google supposedly automates the merging of these images.

I wonder if they are done by humans in innercity imagery or if the street is used as the image-merge line. There don't seem to be any 'split' cars or anything.

See the attachment for a high-detail screenshot from Google Earth if you want to study it in detail.