Taken from Fort Point in San Francisco, shortly after sunrise, March 2010, Sony A700, Tamron 18-200 at 18mm, ISO 200, f/8, 1/90 sec. Post-processing in Lightroom 3.

The shape taken by a rope, chain or cable hanging under its own weight is called a “catenary.” Suspension bridges are designed so that the main cables remain catenaries when the weight of the bridge is added. As an engineer and wannabe photographer, I like that the repeated catenaries in the chain fence and bridge make up leading lines.