Embedded in the sidewalk outside the Doty block (aka the Hotel Carver) at 107 S. Fair Oaks, you will find jewels.
You can find variations of these treasures around town. Try Union Street just west of Raymond, where the purple glass is part of a building. Or along the sidewalks of Mission St. in South Pasadena, where the glistening, glass gems are larger.
Here they are in context, in front of the Doty Block:
I didn't find a listing on the web for W. D. Perine. However, I think I found his office. 28 New Montgomery Street is a San Francisco address, for what it's worth.
Loren Roberts of Hearken Creative Services has his office in the Doty Block. He learned a lot from his current landlord. "The basement of the building used to extend out to below those glass plugs," he says. "Unsure if they were decorative skylights or what. Then the walls got re-built at the line of the building, so those glass plugs don’t look down to anything except open space. But they started getting plugged with cement when the new walls were getting water damage from the outside, where water would come down through the broken glass..." He also said his landlord has expressed an interest in restoring them.
True to form, Loren sent along this fantastic link.
UPDATE: Terry sent this link (right under my nose!) about how the facades were changed in 1929.