So Spoke the Zarazombies

Maybe it is because I have just come back from Namibia, but I feel I am on a different planet.
I had a quick lunch in front of these three guys. I observed them for a while. Apparently, they were friends, only uttering a few exclamations from time to tip but finger-tapping on their respective machines.
When I decided to take a picture of the scene, they did not even notice!