One winner of the Wellcome Image Awards, 2009, for most stunning medical images. Aspirin crystals, under polarizing light in a light microscope.
I found this puzzle very difficult, and had to keep reducing the number of pieces to get something I could actually finish. I’d love to hear how other people fare with it.
Credit: Spike Walker.

2 Comments
After having read your comment, I didn’t even attempt the hard level. The medium level, though, went fairly well.
I managed the hard version, but only in little bits at a time – the window stayed open on my computer for ages while I did other things! It is a stunning image.