In fact we have made cloning and editing even easier by providing "Clone and Edit" buttons on every World page and every course page, so you can get into the editor in one click.
The World here draws some random smiley faces. Click on it to run it.
Exercise for you: "Clone and Edit" the World. Change the values in the box at the top of the code, such as the colours used. Click "Save" and "Run" to see what it does. Don't worry about breaking it. You cannot cause any damage!