While visiting Ireland I noticed small folds that resemble double S to me. This picture was first published on the Mountain Beltway blog written by Callan Bentley. One of my favorite blogs, by the way.
It is such a sweet sight if you are interested in rocks and suddenly see your initials written in stone. I am flattered. The only problem is that this signature has been there for more than one billion years (it formed during the Grenville Orogeny). I guess it actually is not there to honour me.
When I visited La Palma in the Canaries I spotted something similar. This time there is only one S but it is made of dikes.
S-dike in La Palma in the Caldera de Taburiente. It would be very hard to explain why is dike folded like that but this is not necessary because there are actually three dikes that seem to form a letter S.