public static Level genWorldRandom(int cols, int rows, TexturePack tp) {
        /** Brick density. */
        final double pBrick = 0.8;
        /** Probability of a light in the bg. */
        final double pLight = 0.02;
        Level level = new Level(cols, rows, tp);
        
        for (int row = 0; row < rows; row++) {
            for (int col = 0; col < cols; col++) {
                if (GEN.nextDouble() * row < pBrick) {
                    //solid bricks
                    level.setCell(col, row, Texture.brick);
                } else {
                    //background bricks
                    if (GEN.nextDouble() < pLight) {
                        level.setCell(col, row, Texture.bgLightDead);
                    } else {
                        level.setCell(col, row, Texture.bg);
                    }
                }
            }
        }

        level.setStart(new Point(0, rows * Level.CELL_SIZE));
        return level;
    }