This is the old Garfinkel's department store -- a Washington institution that sadly closed some years ago -- now a Borders bookstore. For more pictures of this wonderful old building, see http://www.pbase.com/helenpb/image/91968624 and following image.

I guess there are many lines that converge in this, or at least intersect, but my thought was that the line of windows would converge if they extended far enough.