At dusk, the lights ignite.
The cars shuffling home or to school or to the late shift along Route 309 in Ambler slow, pause, or stop altogether. Drivers inching through traffic on East Butler Pike roll down their windows.
And marvel at Jack Yoast's house and lawn, which are strung with enough Christmas lights to illuminate a theme park.
Which is what the place looks like, actually.
On Tuesday night, six days before Christmas, Yoast stood near his driveway, a necklace of Christmas bulbs flashing around his neck. His brother, in a bright yellow slicker and carrying a glowing wand, was directing traffic to the available parking spots on the road's shoulder.
"Traffic can be a problem," conceded Yoast, tugging on his ear piece.
Yoast moved to the suburbs from Mayfair about 20 years ago. Shortly after he arrived, he spotted a house around the corner with an extensive light display, and showed his oldest daughter.
"She lit up like a Christmas tree," Yoast said.
After he moved into the Ambler house about 12 years ago, he decided to build his daughter her own wonderland.
The basic facts
Roughly 400,000 lights cover the property.
"We've apologized to the neighbors for the inconvenience," he says.
His electric bill is impressive: "Runs us about $2,500 to 3,000 for the season."
The authorities are cool with Yoastland, but occasionally get annoyed when traffic balloons.
He tells his wife, every year, "This is the last year."
Tuesday evening after dusk a shuttle bus of senior citizens from a local retirement home showed up, unannounced.
"They like to see the lights," said Yoast, taking a sip from a Big Gulp. "I usually tell them to come before we open, you know? I got to walk them around. Hold on, give me 15 minutes."
We looked around. The place is laid out like a small fairground. A path guides visitors past displays of galloping reindeer, under arches labeled "North Pole," and toward selfie stations with illuminated Santas.
The jewel is a Cinderella carriage, accented in white lights, and set up for photo shoots in front of the garage. Parents drop their kids inside, pull fingers away from noses and untangle limbs, pleading for smiles.
As Yoast guided visitors around the paths, Julie Forkell coaxed her pink-coated granddaughter to sit in the carriage long enough for a portrait.
"I'm impressed beyond measure," said Forkell, who lives in Souderton. "I get excited when I can get all of the lights working on the Christmas tree."
Around the property one finds red buckets for donations. While Yoast and his company, Acteon Networks, pays for the spectacle, all cash collected goes to charity, he says. This year it's The Kevin from Heaven Foundation.
In the last 10 years, Yoast says he's raised more than $108,000 for multiple causes. And this year, he said, he is ahead of schedule.
Of course, there are issues. Sometimes people don't want to leave. Sometimes they drop cigarette butts. Occasionally Yoast finds dirty diapers. "Dealing with the public comes with its own issues," he said. "But for the 1 percent who are trouble, the other 99 percent make it worth it."
The place will be open on Christmas Eve and Christmas Day, and will run through Dec. 30.
And this could be the last year — if for some reason he keeps his word.