Stasia from Germany writes,
I made this tattoo when I was second year student in physics. Then I had just started my first scientific project and this simple but beautiful shape impressed me. Now I am a Ph.D student in chemical physics and this picture of hybridisation perfectly fits in the area of my scientific interests.
Carl: This is a diagram of pi orbitals (or p orbitals), a particular kind of room in which electrons live. For more, see here. And if you don’t like your pi orbitals tattooed, how about a towering sculpture?