MINNEAPOLIS (WCCO) — Children’s eyes aren’t the only thing all aglow this time of year. If you’ve driven Interstate 94 in the east metro between Thanksgiving and New Year’s, you’ve probably seen a pattern in the office windows of the 3M headquarters in Maplewood.

Each holiday season, 3M lights the windows into the shape of a tree.

“I travel the 94 corridor several times a week, and during the holidays, I just love seeing that tree,” said Holly Wetzel. “It’s just so festive and it makes me happy.”

It takes about 30 lighted offices within the 10,000 person campus.

It’s not that complicated, said Steve Fox, 3M’s manager of administrative services.

“The process in not technologically driven. Basically we turn the timers off and send an email out to the employees.”

Some employees get an email that asks them to leave their lights on and curtains open when they leave work at the end of the day. Others get an email that asks them to turn off the lights and shut the curtains.

“Sometimes there’s random office light off on the side,” Wetzel said.

Fox says there is no strict rule. Usually, if a lit room should be dark, it’s because someone is working late.

“It’s a volunteer thing, there’s no real ramifications,” he said. “The tree is not perfect all the time.”

The tradition started back in 1963 when 3M moved to Maplewood. In 1987, the company made an exception during the World Series and lit the word Twins in their windows. That time, custodians pulled the blinds shut.

“I think it’s a fun thing to do, to share in the spirit of the holidays with our neighbors and the rest of the employees,” Fox said.