JavaScript closures

gistfile1.js

var foo = function (seed) {
  var currVal = seed;
  var incrementor = function () {
    currVal++;
    console.log(currVal);
  };
  return incrementor;
};

var bar = foo(3);
bar(); // Logs 4
bar(); // Logs 5
bar(); // Logs 6

var baz = function (seed) {
  var firstFactor = seed;
  var multiplier = function (secondFactor) {
    console.log(firstFactor * secondFactor);
  };
  return multiplier;
};

var qux = baz(3);
qux(4); // Logs 12
qux(7); // Logs 21
qux(10); // Logs 30