This guy had the first 100 digits of Pi tattooed up his arm and shoulder. 
"A picture of my serotonin tattoo. I don’t know that it needs much more explanation than it’s my favorite neurotransmitter." 
It is a pictorial representation of the Drake Equation.The Drake equation attempts to estimate the number of extraterrestrial civilizations in our galaxy with which we might come in contact.
Where:
N is the number of civilizations in our galaxy with which communication might be possible;
and
R* is the average rate of star formation in our galaxy
fp is the fraction of those stars that have planets
ne is the average number of planets that can potentially support life per star that has planets
fl is the fraction of the above that actually go on to develop life at some point
fi is the fraction of the above that actually go on to develop intelligent life
fc is the fraction of civilizations that develop a technology that releases detectable signs of their existence into space
L is the length of time such civilizations release detectable signals into space.
The tattoo above is a pictorial representation of the above seven factors. It starts out with a picture of galaxy and then each of the element of the equation is shown in a pictorial form.
Here is the Euler Identity, in invisible ink. You can only see it under UV lights.
Speed of light in a dielectric media. 
The Periodic Tattoo of Elements. 
The Feynman diagrams are some of the most intuitive and fascinating constructs in physics. The above diagram shows electromagnetic force being mediated by a photon.
The SMITH chart is a graphical calculator that allows the relatively complicated mathematical calculations, which use complex algebra and numbers, to be replaced with geometrical constructs, and it allows us to see at a glance what the effects of altering the transmission line geometry will be. 
The broken triangle is an illustration of the Gestalt law of closure. The law of closure demonstrates how the mind creates wholes out of parts - and a world out of sensory information - by “filling in the gaps.”
“I’m currently a Ph.D. student studying maths in Australia. Both these tattoos are closely related to the research I’ve done for my Ph.D., which is in the area of elliptic partial differential equations. The top equation is called the Monge-Ampere equation and is the archetype of the equations I currently study. The bottom equation is called the ‘Infinity Laplacian’. The tattoos are meant to represent a memory of the time I spent in my studies.” 
Euler’s Identity is one of the most fascinating mathematical equation. Interestingly, it also shows 9 concepts of math in a single equation: concepts of : 1, 0, pi, e, i, addition, multiplication, exponentiation, and equality. Thanks Cory
ThInK “Out of my interest for Chemistry and my heritage I chose to get his tattoo done almost a year ago. It is on the back of my upper right shoulder and it is a reminder of my philosophy for life “question all objectively.” 
"I found the power equation. It describes the power needed to propel a bike against our everyday foes: gravity, weight, friction, wind resistance. And it describes beautifully the way that the linear components of the resistance give over to the fat slamming wall of wind resistance." 
Pi is such an intriguing number and it pops up at places you least expect it to. No wonder it is a favorite number among the “life mystery lovers”. 
Subatomic Doodling.
