What's Up With The Fort Worth Crease?

So I'm reading NORWOOD by Charles Portis right now (excellent) and I run across a little passage describing the protagonist (the aforementioned Norwood) sitting on the back steps of his house wearing a black hat with a Fort Worth crease.

What's this? A Fort Worth crease? Qu'est-ce que c'est?

I go straight to Google (heard of it?) and slap "Fort Worth crease" into the search box and whoop! Hat crown heaven!

Now, from what I can tell, this is a Fort Worth crease:

According to my research, it's also called the "Hapalong." There are at least a dozen other specific crease names, including the Horseshoe, Rimrock, Centerfire and Two Dot. For the complete list, check out Dave Brown Hats. Good stuff there. According to tradition, the shape of your hat crown telegraphed your political stance to the rest of the world. A flat top crown announced that you held conservative, law-and-order (republican) or Monarchist views. Those at the liberal/democrat end of the spectrum wore rounded crowns. Every hat I had growing up had a Cattleman crown:

This included my favorite-ever navy blue felt hat that I wore to school on Go Texan Day in 4th grade - the same day we got to do special square-dancing on the blacktop and run across to the chain link fence on the far side of the soccer field to squint past the Katy Freeway and see the covered wagons and horses of the Salt Grass Trail Ride pass by on their way to kick off the Houston Livestock Show and Rodeo.

The blue hat was special, too, because it was the first time I was allowed to have the little post card tucked in the inside band that read "Like Hell It's Yours! This hat belongs to:" with my named typed in all capitals on the manual typewriter behind the counter at Potter's Western Wear out in Columbus, Texas. It was kind of like this one:

I had a parent-approved card in my hat with a curse word on it. Clearly, I had crossed a threshold of some kind.

I never had another cowboy hat that I loved as much as that one. They steamed and blocked it right there in Potter's, turning the crown from a Hoss Cartwright into a cattleman before my eyes. I wore it as long as I could stand it (my melon was growing at a pretty rapid rate in those days) - until I'd still have a rather disturbing-looking crease of my own running across my forehead two days after I'd taken it off.

Now that I notice it, if I run my finger reeeeal gently up and down my forehead, I can still feel that crease.

What can I say? It's a dandy hat that makes a lifelong impression.