I thought you could only do it before the polar coordinates
it's neatly done, although a bit too much JPEG artifacts for my taste
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mediocre ha ha ha, you're reading this,
Fri 27 Apr 2007, 19:26,
archived)
i finally found a bit better source in my old photos
a real-live abandoned Lead mine in Iron County, Missouri. ( I cloned the Mystery Machine in there )

Click for bigger (127KB)
...and now I have lost interest in this :)
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PedroHin Come along & ride on a Flantastic Voyage,
Fri 27 Apr 2007, 19:37,
archived)
I like this one better
especially the centre
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mediocre ha ha ha, you're reading this,
Fri 27 Apr 2007, 19:42,
archived)