When I worked out there, I think they were called buck fence. You make an "A" frame, and it almost seems like the top of the A was notched to fit inside each other. At the bottom, a couple feet off the ground, a short lodgepole brace keeps the A from doing the splits. With a couple of these A's made, you then nail about four or five evenly spaced rails (usually sixteen feet long) to start your fence. Next you make another A and put another section of rails in place. About every four sections you need to make a diagonal brace to keep the whole thing from falling over like a stack of dominoes. Just keep building this fence one section at a time until you get as much done as you need.
Back in June of 1970, it was my first day on the job at Moose Head Ranch in Jackson Hole. Another young man and I were assigned to build some buck fence and make a lane by the cabins from the horse pasture into the corral. The owner, a lawyer from Florida, told us to build this fence curved around through the trees. We were nicely started on the curved fence when the year-around caretaker showed up to check our progress. He said, "Make that fence straight. It looks slovenly being curved." We moved everything over and got it straight as a string. Pretty soon the head honcho showed up again and said, "I told you boys to make that fence to curve." We replied that Al told us to make it straight. The Big Boss said, "Make it curved, and don't forget I write out Al's paychecks, too." "Aye, aye," Sir.