Everyone knows the laws of the street score, right? If you see something — furniture, books, art, even clothing — sitting unattended out by the curb and it's not someone moving or a garage sale, it's fair game. I'd even be so bold as to say that almost all of us here have been on one side or the other of that transaction! So while I'm sure we all feel terrible for someone who leaves something outside their home and is surprised when it's taken, one has to ask...how could they not expect that to happen?

But that's the plight of artist Nicholas Coley, who left a blank canvas worth about $200 and $5,500 painting he'd created outside his residence on the morning of Saturday, April 11.

Coley lives in a studio apartment with his wife and two children on Water Street, a small alley in North Beach, the Chron reports.

Given the doubtlessly cramped conditions of his homestead, Coley keeps his art in his garage and shows it to prospective buyers at a donated space nearby. That's what he was doing that Saturday when he left the painting and canvas leaning against the wall of the alley.

“We came back out 15 minutes later and some of the paintings were gone,” Coley told KPIX.

A passing couple, caught on a neighboring hotel's surveillance cameras, saw the painting and canvas and picked them up, likely assuming they had been discarded. You can see a still of them at the top of this post.

“I did shut the garage door, so maybe they just thought they were just like thrown out,” Coley said.

"The canvas is probably only worth $200, but the finished painting is worth about $5,500 in the galleries," Coley told KTVU.

No one thinks the couple had any malicious intent, of course.

"In San Francisco if you put something outside, there’s a very good chance somebody will take it,” SFPD Officer Carlos Manfredi told KPIX.

“They definitely didn’t look like they were trying to steal anything,” Manfredi told the Chron.

“They hesitated before they picked it up like they couldn’t tell if it was free and then they hung around for a second after they grabbed it.”

"They pick it up, they're walking, at one point you see them kissing and they continue to walk away. Sometimes when you don't want an item, you just place it out on the curb and you leave it there for people to take. And people will take it," Manfredi told KTVU, confirming the same street score laws I mentioned earlier.

Though Coley says that he's left stuff outside like that "hundreds of times," he's now focused on getting the valuable artwork back.

"It might’ve looked like stuff nobody wanted...But in this case, that stuff was worth thousands of dollars,” he told the Chron.

"If you have them, please bring them back," Coley told KTVU. "I totally don't want to press charges, I just gotta feed my kids."

“It’s sorta just upsetting," he told KPIX. "It’s how I feed my kids. We have a 10-month-old baby girl and my wife and somehow we’re making a living selling art."

If you have the scoop on the scooped-up canvases, call SFPD's anonymous tip line at (415) 575-4444. According to Manfredi, if the painting is safely returned, no questions will be asked.