gabions

Breach in the north wall of Fort Sumter filled with gabions, 1865. Federal Navy, seaborne expeditions against the Atlantic Coast of the Confederacy, 1863-1865.

Two more weak systems: wicker baskets and piles of rocks that together can fortify a rampart.  This particular kind of gabion can also be found in Viollet-le-Duc's Issu du Dictionnaire raisonné de L'architecture française du XIe au XVIe siècle.  Viollet-le-Duc. Gabions, 1856.

The same system is in military use today: Hesco Bastions are flat wire-reinforced canvas bags that spring open to make a drum which is then filled with material at hand. 

Donovan Wylie. Mountain Position. Mas Sum Ghar. Kandahar Province, Afghanistan, 2011This is a Canadian Forces FOB.  Hesco Bastions form a palisade. It all seems so fragile, scaffolds and gabions, yet they are capable of great protective strength.