As you can see, his friends busy photographing him with their phones, have arrived. If you look closely, you can see another person just beyond the group also busy with a phone.
First, I estimated how far the second pillar was from the first and drew a light line. The top and bottom of the wall can also be indicated. Then I wiped a line in the pastel with my finger to suggest where the spars of the pergola were. That sited the group with the first girl half hidden by the pillar and the others in advance of her. These figures have been sketched in and the walls extended. There is a lovely curling wisteria to put in, climbing the new pillar from this side of the nearer wall . It has a lot more greenery on it, while beyond the far wall and to the right of the new pillar you will see the tops of bushes. All these thing break up the very definite lines of the structure.