They call it an "assurance marker." A few years back, the good folks at the Superior Hiking Trail came up with a simple, affordable way to mark the route of the trail. Blue paint blazes went up on trees and rocks all up and down the trail, even in Duluth. The marks are meant to "assure" hikers that they're still on the trail. And they work. During a long hiking day, I watch for those blazes to keep my energy from flagging,
But I get goofy in the brain, too. To me, the blazes look just the size and shape of an old-fashioned chalkboard eraser, with those thick layers of black felt just waiting to be banged together at the end of the day by the star student. So almost everytime I see one I imagine a precocious second grader teacher's pet, dipping an eraser ever so carefully into a tray of blue paint and applying it to the tree or, harder to imagine, rough rock.
This particular blaze above is on an overlook near Wolf Ridge ELC. In their SHT book, Ron Morton and Judy Gibbs call the bedrock here "tortured basalt."
The SHT blaze system gets more complicated. A white blaze means you're on a spur trail. Two offset blazes mean something like a turn is coming up, watch out.
They even use the blazes on their signs, which seems a bit funky since a blaze is meant for a natural surface. But consistency is comfort.
To me, one of the great beauties of hiking is to let go of worry, to let good trail maintenance and design take over your day, to be guided through some spectacular land. I love rock cairns on slickrock or on the open tundra, the way they say "Hey you human, follow me." In short, I take great comfort in being "assured."