Window Etchings

From TheBestCaseScenario

Window etchings are designs in the side of a window, usually done on an acrylic (plexiglass) surface. They are a great way to add a mysterious element to your case.

Tools used may be Exacto Knives, a Dremel (with engraving/etching bits), or in some cases, lasers.

Most designs are first outlined using a sharp object (Exacto Knife), and then filled in with a dremel etching bit.