This is a great gift for any math geek. This analog watch is filled with math equations instead of normal numbers. Though there are a lot of interesting Apple iWatch Rumors, this is definitely the watch that will make your geek friends jealous.
Perrelet also has a skull watch among its series of turbine watches, known for their spinning blades on the dials. The Turbine Toxic Special Edition bears the image of a skull and crossbones, visible when the wheel spins.