There's a flare from the camera flash that seems to be focussed directly on the most marked part of the black plastic as well, which might be a clue...

Of course, I could be totally wrong and maybe it's short-sighted raccoons trying to steal the lenses to fashion into rudimentary spectacles... we don't have raccoons over here!
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Geoff
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Mk1 Blue - was 4GB, now 16GB
Mk2 Red - was 12GB, now 60GB