@Baenefin, I do not think that is possible. Either you gave the wrong line number, the error was not in the SWorld class or you edited the class (which I specifically requested not be changed in any way).

@Entity1037, if you think this is difficult ... try the challenging one (with the numbers). All the cubes have to be in exact ending location in that one. Here, at least you exchange one of one color with another of the same color while getting others in place.

Sometimes the more basic, the better. Take for example my Viral Spiral scenario. It was the basis for 'Viral Spiral Polygons' and for 'Viral Spiral Controlled'; yet, the original got many more votes than the more involved take-offs. I do not know -- maybe because you actually see the arms swinging around in it?

You can also, then, start it in the 'started' method in the world. There are probably information tags in your sound file(s) that need to be removed so they do not throw ArrayOutOfBoundsException errors when the sound file has completed a loop.

I suggest moving it back to your World sub-class and making it a 'static' field. Then in your Monster class you can use: 'WorldClassName.bgSound.stop();'.