Ron and his wife first noticed the sign along the Malahat highway about a year ago. 

"We kinda went, 'Oh!'" he recalls. "I wonder what that is?" 

If you're driving north the sign is an unremarkable fluorescent orange triangle. But if you're heading south, you'll see an ever-changing image, that today happens to be a dog. 

"We started looking for the sign," Ron says fondly. "We started looking for the change."

I'm talking to Ron on the phone after he and his wife Lisa sent me an email saying how much they appreciate the sign. They and thousands of others who drive past the signs every day don't know who's making them or why. 

So after three arduous attempts to get to 1460 Malahat Drive – I now know the u-turn routes at Bamberton and South Shawnigan Lake well – I'm wandering up one of the few driveways around here, in search of the meaning behind the mystery. 

I walked to the top of the very steep property the first time I tried. Nobody was home, so I left a note. 

The second time, I met Colin and his partner Kristina, who live at the top of the mountain. "Oh! We love mysteries!" he exclaimed. "They're great!" 

But Colin says the sign isn’t a great mystery at all. He and Christina made the first sign – a decorated Christmas tree – to warn winter visitors about the ditch beside the driveway. "People made it and nobody was in the ditch," Colin recalls. "So that was the good thing."

The bad thing he says is he didn't take the tree down for months. "We had our Christmas tree up in April!" he laughs.

So Christina and Colin decided to change the sign and start celebrating all year long. Over four years, they've crafted dozens of colourful signs, from the expected (Easter, Remembrance Day, Halloween) to the unexpected (Pay Day, Humboldt Strong, Olympic Medal Count).

"The medal count was changed every day," Colin says. "Christina did that religiously."

They did it for the thousands of people who endure the daunting drive daily. "To make people smile for a split second," Christina says. "As they drive to work or drive home."

And because the Malahat can feel so inhospitable, they hope to help strangers start to feel like neighbours. "There's no one to talk over the fence with," Christina says. "We hope to develop a sense of community."

It seems to be working. A couple of people have left them handwritten thank-you notes beside the sign. One person even gave them a $25 gift certificate to fund more sign supplies.

There are countless others who have posted their appreciation online. The unrelated strangers are now expressing common condolences about today's sign (a silhouette of a dog with a rainbow over its head), after concerns it means a furry family member has died. Colin confirms it's true.

"It's tough missing her," he says. "It's only been two weeks." The new sign is a tribute to their dog Bailey, and a celebration of how she lived her life. "She was a super happy dog," Colin says. "And that's the main thing, right?"

And the main reason, Colin says, this is no mystery. This is just a couple neighbours spreading happiness one sign at a time. "If you can make a difference in the world," Colin asks. "Why wouldn't you?"