$(function() {
  setTimeout(moveLeft, 250);
})

function moveEyes() {
  $('#eyes').animate({
    left: '+=10',
  }, 750).animate({
    left: '-=20',
  }, 750).animate({
    left: '+=10',
  }, 750);
  setTimeout(moveEyes, 5000);
}

function moveLeft() {
  $('#eyes').animate({ left: '+=8' }, 750, 'jswing', function() { setTimeout(moveRight, 500 + Math.floor(Math.random()*500)); });
}

function moveRight() {
  $('#eyes').animate({ left: '-=16' }, 750, 'jswing', function() { setTimeout(moveReset, 500 + Math.floor(Math.random()*500)); });
}

function moveReset() {
  $('#eyes').animate({ left: '+=8' }, 750, 'jswing', function() { setTimeout(moveLeft, 5000 + Math.floor(Math.random()*2000)); });
}