A very vivid memory from my time at art school was a visit by buddhist monks creating a mandala. I was amazed by the patience and focus it must take to create such a work. Many years later and we were fortunate to have a travelling group creating a mandala in the foyer outside our studio last week.
I find it amazing that the monks could spend a week bent over their labor and then wipe it away when it was complete. Renata mentioned that after spending a week on such an intense drawing, erasing it away afterwards would be pretty traumatic for her! (me too)