Mountain generation

private void generateMountain(int startX, int startZ) {
        Material[] layers = new Material[]{Material.STONE, Material.STONE, Material.GRASS};
        boolean[][][] mountain = new boolean[][][]{
            {
                {true, true, true},
                {true, true, true},
                {false, true, false}
            }, {
                {false, true, false},
                {false, true, true},
                {false, false, false}
            }, {
                {false, false, false},
                {false, true, false},
                {false, false, false}
            }
        };
        for (int x = 0; x < 3; x++) {
            for (int z = 0; z < 3; z++) {
                for (int y = 0; y < 3; y++) {
                    world.getBlockAt(startX + x, 64 + y, startZ + z).setType(layers[y]);
                }
                for (int y = 3; y < 6; y++) {
                    world.getBlockAt(startX + x, 64 + y, startZ + z).setType(mountain[x][y-3][z]?Material.STONE : Material.AIR);
                }
            }
        }
    }