In 1998, the architect Matteo Pericoli started drawing the Manhattan skyline, building by building, on two thirty-seven-foot scrolls. A section of Pericoli's drawing, showing lower Manhattan from the west, ran in The New Yorker in 1999. For the 10th anniversary of September 11th, Pericoli drew that same section of the skyline again, and you can compare the two drawings in this week's issue of the magazine. Here Pericoli talks about his relationship to New York City, his drawing process, and how the skyline has changed in the past dozen years.