old_contents: var Wave = function(game, x, y) {
  	this.game = game;
  	Phaser.Sprite.call(this, this.game, x, y, 'wave');
  
  	this.initialPos = { x: x, y: y }; // looks ugly, should be es6 already!
  }
  
  Wave.prototype = Object.create(Phaser.Sprite.prototype);
  Wave.prototype.constructor = Wave;
  
  Wave.update = function() {
  	var time = this.game.time.time / 1000;
  	this.y = this.initialPos.y + Math.sin(time) * 100;
  }
  
  var Ocean = function(game) {
  	this.game = game;
  	Phaser.Group.call(this, this.game);
  
  	this.waves = [];
  
  	for(var y = 0; y < 10; y++) {
  		for(var x = 0; x < 10; x++) {
  			/*var wave = game.add.image(x*100-100, y*75-100, 'wave');
  			this.add(wave);
  
  			this.waves.push(wave);*/
  
  			var wave = new Wave(this.game, x * 100 - 100, y * 75 - 100);
  			this.add(wave);
  
  			this.waves.push(wave);
  		}
  	}
  }
  
  Ocean.prototype = Object.create(Phaser.Group.prototype);
  Ocean.prototype.constructor = Ocean;
  
  Ocean.prototype.update = function() {
  
  }
  
new_contents: var Wave = function(game, x, y) {
  	this.game = game;
  	Phaser.Image.call(this, this.game, x, y, 'wave');
  
  	this.initialPos = { x: x, y: y }; // looks ugly, should be es6 already!
  
  }
  
  Wave.prototype = Object.create(Phaser.Image.prototype);
  Wave.prototype.constructor = Wave;
  
  Wave.prototype.update = function() {
  	console.log('test');
  	var time = this.game.time.time / 1000;
  	this.y = this.initialPos.y + Math.sin(time) * 100;
  }
  
  var Ocean = function(game) {
  	this.game = game;
  	Phaser.Group.call(this, this.game);
  
  	this.waves = [];
  
  	for(var y = 0; y < 10; y++) {
  		for(var x = 0; x < 10; x++) {
  			/*var wave = game.add.image(x*100-100, y*75-100, 'wave');
  			this.add(wave);
  
  			this.waves.push(wave);*/
  
  			var wave = new Wave(this.game, x * 100 - 100, y * 75 - 100);
  			this.add(wave);
  
  			this.waves.push(wave);
  		}
  	}
  }
  
  Ocean.prototype = Object.create(Phaser.Group.prototype);
  Ocean.prototype.constructor = Ocean;
  
  Ocean.prototype.update = function() {
  
  }
  
subject: Edit ocean.js