Louis I. Kahn at The Paris Review:
One day, as a small boy, I was copying the portrait of Napoleon. His left eye was giving me trouble. Already I had erased the drawing of it several times. My father leaned over and lovingly corrected my work. I threw the paper and pencil across the room, saying “now it is your drawing, not mine.” Two cannot make a single drawing. I am sure the most skillful imitation can be detected by the originator. The sheer delight in the act of drawing has its way in the drawing and that also is a quality that the imitator can’t imitate. The personal abstraction, the rapport between subject and the thought also are unimitatable.
In the presence of Albi [Cathedral], I felt the belief in the choice of its architectural elements, and what exhilaration and patience were combined to begin it and work toward its completion.
more here.