The Seattle UrbanSketchers group met yesterday at the Seattle Bouldering Project, a climbing gym that offers a range of classes to introduce beginners to the sport as well as help more experienced climbers develop techniques for strong and skilled climbing. This view, which was drawn from the mezzanine level, began with blocking out the basic volume of the tall space. Then it was a matter of filling in with the climbing volumes and walls and pertinent details.
Here is another view from below. Trying to capture the climbers themselves was difficult because of their constant movement so all you might be able to see are their ghost images.