Recently, there was an interesting article in the San Francisco Chronicle by John King about various Flatiron Buildings around San Francisco. The three cornered buildings got their name because they resemble a clothes iron face down from above, and the most famous Flatiron is the Fuller Building on 5th Avenue in New York. The article had me looking back over my posts to see how many of the Flatirons mentioned in Mr. King’s article appear in some of the updates I’ve posted in the past. I’ll include the link to John King’s article at the end of my pictures. (Thumbnail images)
First is the Phelan Building at 760 Market Street in an update of a 1910 photo I did in September of 2016. The Phelan Building was built in 1908.
800 Market Street, built in 1908 as well, in an update of a 1942 photo I posted in February of 2022.
548 Market Street in an update I did in August of 2021 of a Minor White photograph. Like the Fuller Building in New York, this one, built in 1913, is called the Flatiron Building too.
This one on the corner of Columbus Avenue and Kearny Street wasn’t in John King’s article but it could have been. I couldn’t get a date on when it was built. You can see the old Finocchio’s in the vintage picture.
The last two are of probably the most popular Flatiron in San Francisco, the Sentinel Building, also known as Columbus Tower, opened in 1907. The top photo is from 1910, the bottom one from the early 1960s, is from the Cushman Collection. Below is the link to John King’s article in the Chronicle.
https://www.sfchronicle.com/projects/2023/sf-flatiron-buildings/
San Francisco Film Locations Then & Now 
How many do you suppose saw them from above back then? Perhaps their description came from plans, or developed afterward.
They used their imagination. 😉
and maybe street maps. The roofs are likely shaped like the parcels below them.
or perhaps someone was abducted by space aliens!