It's Georg Christoph Lichtenberg's birthday (July 1st, 1742). His discoveries paved the way for modern xerographic copiers, and led to an early understanding of electric discharges.
Fun fact: his title in 1769 was "Professor Extraordinarius"
(in German: außerordentlicher Professor).
Let's talk about Lichtenberg figures like this one created by subjecting an acrylic block to an electron beam charged to several megavolts with a pin embedded in the base.
You're seeing the path that the charged plasma took through an insulating material. Like lightning, but crystallized.
