While I was visiting my parents I availed myself to reading the dead tree version of the local newspaper The Sun-Herald and went to the Opinions and Editorial section.
I found a piece written by Molly Ivins that caused a few chuckles as I saw her practice journalistic sleight of hand to push her opinion up hill in regards to immigration and securing the border.
She talks of a section of cyclone fence [17ft tall] with 'bob-wire' being defeated in thirty seconds. Now being someone who spent a bit of childhood on a farm I was puzzled by 'bob-wire,' was Molly so eager to write this piece she forgot it is called barb-wire? Well to my chagrin some people do call it 'bob-wire' so that idea went out the window. The photo titled A is barb-wire as it is typically put atop cyclone fencing. This is meant to keep the average mischief maker out of places like storage units or auto junkyards. It can be used for more important situations but it would need upgrading, like motion sensors to detect someone climbing it. A truth about this type of barb-wire in this arrangement is this, it is easy to get over. Someone just needs to toss a denim jacket or a jacket of similar heavy material over the three strands, pull the sleeve through the gap in the bottom, pull it as hard as possible to collapse the strands, and tie it off to itself - or just use a set of wire cutters.
Next lets look at photo C which is an example of cyclone fence as used on a tennis court. You notice the gaps in the fence as the bent pieces of thick wire are interlocked to make the fence. It is this interlocking that gives this fence its more popular name: chain-link fence. Each of these gaps can give a determined person a handhold and foothold to get up and over the fence. Or if our intruder is better prepared then a good set of wire cutters will go through this chain-link fence in a matter of minutes.
So you can now understand how fallacious Molly Ivins' charming little anecdote is. What is picture B you are wondering? This is what the military deployed on the Mississippi Gulf Coast to keep people out of the destroyed areas after Katrina. This particular multi-strand of concertina wire ran parallel to the railroad tracks that went through Long Beach, MS. Another name for this stuff is razor wire. Each barb has two very sharp points that seem to be very long and since it is not a round but a flat profile the wire itself is very difficult to cut. To roll it up, one has to use special heavy mittens that has metal links embedded in it.
And to further demolish Molly's little piece, the Great Wall of China failed because the barbarians could go around it or they just raided the trade caravans out of sight of the wall. Do not think the theoretical fence to separate the United States from Mexico will have to worry about exposed endpoints. Now the Israelis are building a proper reinforced concrete wall to keep the homicidal Arabs contained to Gaza and that should serve as a good model for whatever is built in the United States.
For a look at what is facing Mississippi and its Gulf Coast please read this article from GCN about all the changes that will be happening to make the place more resilient to hurricanes.