The silver metal circles starting popping up on Berkeley sidewalks this summer, but no one seems to know who the creator is.

There is a person out there with a sly sense of humor, a way with words, a working knowledge of Berkeley history and a desire to impart pithy observations.

He or she or they has been going around town the past few months affixing round metal medallions with clever sayings to sidewalks around central Berkeley.

“Welcome to Berkeley. Now stop doing that,” reads one medallion nailed into the sidewalk near the Berkeley/Oakland border. The other half of the medallion says: “Welcome to Oakland. We missed you.”

Another states: “On this spot, ….David Kravitz finally thought of a witty rejoinder after that dreadful dinner party a week earlier. Mr. Kravitz had wished to say at the time, ‘Some suffer in silence, but others make everyone suffer each time they open their mouth’ to that loudmouthed Mrs. Pearlman.”

A third located at Delaware and Sacramento streets says, “On this spot, you are directly here. You could have been anywhere else at this moment, rendering this plaque irrelevant, but you’re not.”

No one seems to know the creator’s identity, even though the question has been posed on Facebook and Twitter and even on Tom Dalzell’s Quirky Berkeley website.

“These days, just everybody – tout le monde – is talking about the mysterious medallions that are appearing in Berkeley’s sidewalks,” Dalzell wrote. “You read about them in Berkeleyside, you see them on Twitter, your hip friends are talking about them. “Plaque” might be a better word for what these are, but medallion gives us alliteration with mysterious.”

The person has followers, people who appreciate their use of words and phrases, their deadpan delivery and the unexpectedness of the medallions.

“This miniature plaque is embedded at a bus stop near the Rose Garden,” Natasha Beery posted on Facebook on Aug. 8 with a picture of the medallion. “It is one of a series of mysterious markers turning up around town. Have you seen others?”

Subscribe to the Daily Briefing Don’t miss a story. Get Berkeleyside headlines delivered to your inbox. Don’t miss a story. Get Berkeleyside headlines delivered to your inbox.

The medallions started appearing in April

Doug Sovern, a political reporter for KCBS Radio, first spotted the Oakland/Berkeley medallion in April. Colleen Neff, who contributes photos to Berkeleyside and Quirky Berkeley, reported that she first saw one in May. (She noted that the creator misspelled Shattuck Avenue as “Shattack.”)

Karen Flynn, the owner of The Optician on Allston Way just east of Shattuck Avenue, first spotted one of the mysterious medallions in July.

“I was out cleaning the windows and I looked down,” she said. “At first I thought it was something serious but then I read it and thought ‘that’s funny.'”

The medallion by her store is titled “Strawberry Creek,” and it indicates that the creator is familiar with Berkeley geography. It reads: “On this spot, the Strawberry Creek flows deeply buried below this sidewalk … no longer posing a threat to surface dwellers.” (Strawberry Creek runs freely through the UC Berkeley campus but is undergrounded when it hits downtown.)

Another medallion at 1900 Fourth St. — a parking lot across from the now-shuttered Spenger’s restaurant — refers to one of the most contested pieces of land in Berkeley. The property is owned by the Spenger family and Ruegg & Ellsworth, who have sought to build housing there. (Read more on the intricacies.)

Native Americans in the area have protested, as they say the land is sacred to them. One developer tried to get it fast-tracked, evoking California’s SB 35, but the city rebuked the effort. The matter is now in in court.

Is the creator hammering the metal medallions into the sidewalks under the cover of night? During rush hour when people’s attentions are distracted? Why has no one spotted him/her/they in action? #mysteriousmedallions

Update: As more information emerged, this story was updated to report that the first medallions were spotted in April rather than this summer.

Frances Dinkelspiel is co-founder and executive editor of Berkeleyside.