return largest numbers in arraya FreeCodeCamp challenge
function largestOfFour(arr) {
  var out = [];

  for (var i = 0; i < arr.length; i++) {
    var iii = 0;
    for (var a = 0; a < arr[i].length; a++) {
      if (iii < arr[i][a]) {
        iii =  arr[i][a];
      }
    }
    out.push(iii);
  }

  console.log("RETURN => ", out);
  overlay([out]);
  return out;
}