Here is something I look at every working day – the edge of the El platform.  The composite material is the surface of the Clark and Lake Blue Line stop, near my office. The blue is the skidproof edge of the platform – beyond it, the plunge to the track bed, the puddles of garbage-strewn water and the electric rails.   I look at this every morning and evening and, frankly, the place is dirty and dark and crowded with office workers like me and students going to and from college and insane beggars and musicians of wildly varying gifts and tourists heading for the airport or to get drunk in Bucktown and the occasional pairs of police officers completely absorbed in conversation with each other, and I love it.  It’s a good part of my day, standing on the platform.