For the simplest case yes, a way of bending big pipe and some way to make two big holes in the ground to then cement the thing in. (Or similar) But it quickly g

For the simplest case yes, a way of bending big pipe and some way to make two big holes in the ground to then cement the thing in. (Or similar) But it quickly gets complicated - making smaller holes in concrete type surfaces is easier, less intrusive, less permanent than making bigger holes, which can lead to the flange method, but then you need some way to make or buy flanges, and then stick them onto the pipe. I make my own flanges out of plate and weld them on but you could go with threaded flanges, I think Home Depot (or similar) can thread high diameter pipe for you. You can also skip the pipe bender by mitering two pipes together with a welder or doing like a pie cut thing. I do that kind of thing for pipe that's harder to bend - bend it to 45deg, miter cut and weld to 90 is a common technique for me. If you look up how DIY car exhausts are fabricated there's a lot of relevant tricks there. With a grinder and some elbow grease you can make it look like it was never welded. For the finishing touch it's nice to have a friend with a galvanizing and powder coating shop :)