http://www.knuckletattoos.com/singularity/

I never thought I’d say this but, “I wish I was more math savvy so I could get that hardcore tattoo” You’ll have to read the explanation if your skin sees more than 2 hours of sunlight a day.

Also there are a great many more knuckle tattoos that will simply astound you by their irreverence… and LOTS of dirty fingernails.