Stone, brick, earth, wood

Steep slopes of earthen fortifications were maintained by means an intricate system of compressed layers of earth and by planting special species of grass. It was couch grass that bound the slopes most effectively. Small cubes were cut out from couch sod and placed stepwise ….with the roots upwards! Couch grew deep and bound up the cubes into one flexible green mattress. This way of strengthening earthworks was called “plekwerk” i.e. couchwork. Till the invention of exploding shells, such covering of embankments had effectively dispersed the energy of spherical demolition shells.