code: function ComputerController(ball) {
      var myHandle;
  
      this.mount = function (handle) {
          myHandle = handle;
      };
  
      this.dismount = function () {
          myHandle = null;
      };
  
      this.step = function () {
          if (myHandle) {
              if (myHandle.y > ball.y) {
                  myHandle.move(Math.random() * 2 + 1);
              } else {
                  myHandle.move(-(Math.random() * 2 + 1));
              }
          }
      };
  }
docs: Controls a handle by computer (naive computer vs player)