so many houses have front gates in San Francisco. they typically cover the entire front door area, so that one can’t even reach the front door without getting through the front gate. only a kitten or skinny squirrel could squeeze through!
i’m sure this started as a utilitarian safety feature (think a second front door). but now that they’re a ubiquitous feature, you can find so many different designs:
they’re as much a part of San Francisco architecture as any other deco fixture or brightly colored stucco slab.