PixelPals – Collaborative pixel art canvas(eternalthinker.github.io)

   var socket = new Firebase("https://pixelpals-server.firebaseio.com/public");
   var w = 150;
   var h = 120;
   var randColor = function(){
   	return '#'+Math.floor(Math.random()*16777215).toString(16);
   };
   for(var i = 0 ; i < h; i++){
   	for(var j = 0 ; j < w ; j++){
   		socket.child(i*w + j).set(i%2 ? randColor() : '#000');		
   	}
   }