Drawing a rainbow in AI

When I started learning AI, I soon learnt to use the gradient tool because I was involved in writing a photodermatology review that required a figure of an electromagnetic spectrum. This inspired me to draw a rainbow for fun but I just couldn't find a way to do it with the gradient tool. Finally I realised last night I knew how to do it. First apply a radial gradient to a circle. Next draw a rainbow shape with two circles and a rectangle using the shape builder tool. Then finally make a clipping mask and there is the rainbow.

Dolphin skin

I joined the BBC documentary 'Dolphins; Spy in the Pod' at the point when David Tennant mentioned that Dolphins shed the outer most layer of the skin every three hours. I immediately wanted to see the scientific evidence and found a paper in the Journal of Investigative Dermatology by Hicks et al in 1985 which does indeed suggest a very fast sloughing rate. The microscope images look fascinating but sadly they are in black and white and low power. Back then it was so expensive to publish in colour so we rarely did.