This is very interesting. Here the gravel meets two other hardscaping materials, which is the maximum number of different types of hardscape materials you should have in any one yard. Notice how the dark grey of the gravel defines the two spaces as separate. If you were walking on this path into the patio in the picture you would now the moment you arrived at your destination. Notice the difference in feeling between the straight path in the previous photo and the curved path above. Which do you prefer?