I've had my eye on Mac Williams' tree house for some time. Nestled in a pear tree next to his driveway, it conveys the essence of what tree houses are about.

A couple of winters ago I took a color photo of it just as the sun was setting. The surrounding snow had a violet cast. In the background, it created a golden wreath around the tree house, bathing the scene in an almost sacred atmosphere of summer play now settled into winter hibernation.I've often thought that Mac and Avera were to be commended for leaving the tree house in place. She is in her 70s and he is 83, going on 84. Most people would see a tree house so prominently placed in the yard as an eyesore. It wouldn't take many years after the kids were raised to find a sensible excuse for tearing it down.

The only thing I could figure is that they kept the tree house as a memorial of sorts. Maybe looking at it brought pleasant memories of when their children were young.

A few weeks ago I decided to do an etching of Mac and Avera's tree house. I could imagine what they might think if they looked out their window and saw me sitting in the garden. So, lawn chair under arm, I rang their doorbell.

I know Mac and Avera fairly well. Mac and Veloy's dad were close friends in high school in the 1920s. During World War II, Mac and Avera moved to L.A. where he helped build war planes for Lockheed. They even thought of staying in California, but back in Utah, Mac's mother's health was deteriorating, so they came back to help her take care of the farm and stayed.

Newspaper in hand, Mac opened the door and invited me inside. Avera came in from the kitchen, wiping her hands on a dish towel.

"Would it be OK with you if I do a drawing of the tree house north of your driveway. It's such a neat tree house, etc., etc., etc., and I'll be careful not to step on the raspberries, etc., etc. . . ."

Everything was OK with them. I could sit out there in the chilly October afternoon just as long as I pleased. And by the way, says Avera, it wasn't built by the kids. Mac built it.

I picture Mac, back in the 1950s, helping his kids build a tree house. Come to find out, that image is also a bit inaccurate. He didn't build it for his kids. He built it for his grandchildren . . . and not in the '50s, but in the '80s.

That would mean Mac Williams built his tree house when he was well into his 70s.

As I sat out with the pumpkins and worked on my etching of Mac's tree house, I couldn't help but marvel at the idea of a man in his 70s building a tree house.

High limbs are a natural latticework for the dreams of children. Usually, though, by the time we grow up our dreams have been drastically trimmed. By middle age, the pruning is complete, and most of us settle with half dreams at best and resolve to tough it out anyway . . . or so we often see it.

Whether he knew it or not, Mac built his tree house as a celebration of the human spirit. I doubt he saw it that way. He wouldn't have. He was just building a tree house. That's what makes it so special.