Lichtenberg figures

Branching shapes that, like tattoos, appear for hours or days on the skin of some people after being struck by lightning. Those marks reflect the path of the electrical discharge across the skin. Their reddish color is due to the rupture of small superficial blood vessels, caused by the passage of the electrical current and the sudden heating it causes. These arborescent figures take their name from the German physicist and writer Georg Christoph Lichtenberg (1742-1799), who was the first to observe them on electrically charged plates. The dust deposited on them formed the figures. This fractal-geometry pattern arises both on the surfaces and inside insulating materials, when an electrical current of a certain intensity flows through them.