Have a look at the mathematical formula tattoo above. I’m sure, like many other people, mathematics is not the favorite subject of this person and may be he is poor at remembering the mathematical formulae. What else could have encouraged him to get this formula inked?
The formula in the picture above is a fixed-point combinator in the lambda calculus and was discovered by Haskell Curry. This formula calculates the fixed point of a function which allows for recursion by calling on that fixed point. Recursion is the most important concept in Computer Science.
Whatever be the reason of this person getting this formula inked, I think students who forget the mathematical formulae will surely like the idea and may be they get the mathematical formulae inked on their body before taking their next maths exam!