Hurdles: On Building Split-Rail Fences and Portable Fences

An expert on vintage (i.e.: pre-power tool) hand crafting techniques describes the process of building split-rail fences and "hurdles" or portable fences.

split-rail fences, portable fences - twisting a weaver
Giving weavers a twist when they twine about an upright will, ironically, keep the fence section itself straight.
Roy Underhill