The Euclidean algorithm to compute the greatest common divisor of two numbers.In Javascript, if you have two numbers x and y that are both greater than zero, you compute the greatest common divisor xyGcd in one beautiful line of code:`````` var xyGcd = function gcd(a,b){ return b ? gcd(b, a%b) : a; }(x, y); `````` In my opinion this is the greatest one-liner ever.

 > In my opinion this is the greatest one-liner ever.I dunno, I really like Haskell's one-line infinite Fibonacci sequence:`````` > let fibs = 1 : 1 : zipWith (+) fibs (tail fibs) > take 7 fibs [1,1,2,3,5,8,13] > fibs !! 1000 70330367711422815821835254877183549770181269836358732742604905087154537118196933579742249494562611733487750449241765991088186363265450223647106012053374121273867339111198139373125598767690091902245245323403501 `````` I don't think it's the most efficient solution, but it really showcases lazy evaluation with a simple example.
 Isn't it a-b instead of a%b?
 a % b is a way to do it in fewer iterations than a - b.

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