The samples look reasonably good, although I'd prefer to see them a little "thicker".
Whatever is built should be about 30 feet high -- not going to be easy to use an ordinary ladder on a barrier that high.
The overhanging spikes on top are a good touch.
Guard towers will be needed, as well.
Then again, as some in this forum will remind us:
"Just remember....walls don't work".
Who sez?