I've blogged about it before and as long as it rains in Norway I'll blog about it again. It's those patterns in the fjord again. This time is particularly interesting because of the two spirals that look just like the UWC logo. One of my students, from a couple of years ago, Wojciech wrote his EE on the subject and verified (I think) that it is caused when the splash made by falling raindrops is subdued by a thin film of oil on the surface. So, what you see is the swirling pattern made by oil that has leaked out of passing boats. Ever heard of pouring oil on troubled waters, well an oily layer does calm the water. I once had a minor accident with my motor boat and spilt a bit of petrol on the fjord. Caused a massive stripe across the water. Another EE could be using the effect to plot the currents, which in this case would be very interesting.