Tattoos and college students

I was at the fitness center and looked at the young woman to my right while on the elliptical aerobic machine - she was wearing two tops, a short one, and a sleveless one on top and there was a part of her side exposed, and a tattoo that was vertical that looked like an electrical engineering circuit. I mean it really looked odd. then I thought, maybe a surgeon drew that on her and she was going to be operated on (my surgeons would draw on me before surgery too, kinda like an engineering plan) but then I thought why would that still be on her? Then I realized, it was a tattoo she must have wanted and it looks like an electrical circuit. Of course its creepy that I am starring at the side of a young woman's bare tummy....I listen to my ipod and read a novel at the fitness center to block out everything around me so this was unusual. Is a circuit board the strangest tattoo you have ever heard of?