Bernard Bertram tracks his yuletide joy on a spreadsheet.
The retired programmer has strung precisely 20,171 twinkling Christmas lights on his Burnsville home and lawn this season. He keeps printouts of his Christmas light stats and instructions on their exact placement in a red binder.
Bertram, 68, has a master's degree in math and a lifelong passion for outdoor holiday illumination. Christmastime is a happy marriage of holiday merriment and mathematical minutia.
He has decorated for the past three decades, and this year he's one of a handful of homeowners competing for the top prize in the 2012 Burnsville Winter Lighting Contest held by the Burnsville Convention & Visitors Bureau and the Dakota Electric Association.
"It's very relaxing for me. I find it very enjoyable," Bertram explains as he thumbs through his red binder at the kitchen table.
"When I go out and I see something is not working, it's a challenge to fix it."
From Thanksgiving to the epiphany each year, Bertram's two-story home and lawn at 15113 Stevens Av. are ablaze in a halo of Christmas lights and lit figures.
Bertram divides his display in two.