Function gcd

modules/gcd/gcd.js:9–12

(u, v)

    var a, b, stack

    function gcd(u, v){
      stack.push({u: u, v: v})
      return v ? gcd(v, u % v) : u
    }

    while (!stack.length || stack.length < 4 || stack.length > 5 || _.last(stack).u < 5){
      a = 960 - Math.floor(Math.random()*400)