I know. I am not a design engineer. I barely graduated high school. So maybe this thought is all wet. None the less, I just have to suggest it.
First there is the there is possibility of using clear plastic. It would probably be a good idea to enclose some kind of wire mesh for strength. It would have three big advantages, maybe four or five. It could be built very fast. It could easily be repaired. There is no way for someone to climb a smooth plastic surface. To be sure, it would be transparent. I am guessing that plastic is less expensive than steel. In cars, they keep replacing steel with plastic, I guess, because it is less expensive. It is certainly lighter and likely easier to mold.
My second consideration is fiberglass. I am sure that fiberglass would have most of the advantages of plastic but it would not be clear. Still, plastic windows could be built into it. I don’t know how fiber glass compares in cost with steel, but they sure build a lot of boats from it. If must be at least competitive with steel. Moreover, it is far easier to repair than steel or plastic. In all likelihood, the patch could be made stronger than the the original wall. The fiberglass would also have one more big advantage. Sensors could easily be hidden in the wall that could sense noise and changes in light. Also, speakers could be installed so that warnings and/or sirens can go off the instant someone tries to go over or under the wall.
Maybe someone out there who has some knowledge on the subject can tell if I am going astray with these thoughts. Certainly, if plastic or fiberglass is better, someone else would have thought of it.
Actually, I just had another thought. The plastic could have gravel inside it. I’m not sure, but I think maybe small rocks or gravel might be less expensive plastic. It just might also have a side benefit, it might have real nice esthetic values.
Regardless, it might be a good idea to coat the wall on both side with some good slick grease. First, it will make it more difficult to climb. Second, no one wants to get grease all over themselves. Third, if someone does manage to scale the wall, it will be easy to tell. He will will have grease on him.