public static World generateWorld() {
        World world = new World();
        
        for(int i = 0 ; i < 200 ; i ++){
            for(int j = 6 ; j < 15 ; j ++){                
                world.addBlock(i, j, new AirBlock());
            }
            for(int k = 200; k>=0; k--) {
                double r = Math.random();
                if(r < 0.01) {
                    world.addBlock(i, k, new AirBlock());
                }else if(r < 0.2) {
                    world.addBlock(i, k, new StoneBlock());
                } else if(r<0.24){
                    world.addBlock(i, k, new DiamondBlock());
                } else if(r<0.28){
                    world.addBlock(i, k, new CoalBlock());
                }else {
                    world.addBlock(i, k, new DirtBlock());
                }
                
            }
        }        
        
        return world;
    }