Modern 3D<unk> s or "electrical treeing" in a block of clear acrylic, created by irradiating the block with an electron beam. Actual size: was created by current from a nearby lightning strike A<unk>  (German<unk> n), or<unk>  dust<unk> , is a branching electric discharge that sometimes appears on the surface or in the interior of insulating materials.<unk> s are often associated with the progressive deterioration of high voltage components and equipment. The study of planar<unk> s along insulating surfaces and 3D electrical trees within insulating materials often provides engineers with valuable insights for improving the long-term reliability of high-voltage equipment.<unk> s are now known to occur on or within solids, liquids, and gases during electrical breakdown.<unk> s are natural phenomena which exhibit fractal properties. The emergence of tree-like structures in nature is summarized by constructal law.
Lichtenberg figure
Silk-glove sign
Thurstan Holland sign
Crichton-Browne sign
Gorlin sign
Asboe-Hansen sign
De Musset's sign
Bow and arrow sign