A wall of weathered wooden planks supported by rusted I-beams. It is 4m high by default but there is a further 3m below ground if you need it.
The spline has 4 different repeating units shuffled randomly every time a spline point is moved. Repeat unit LOD meshes contain 38, 18 and 6 triangles plus 1 texture material, culled at a nominal 4000m. Requested by Poolboy. Made in 3DS Max 2009.