A Julia set is something that mathematicians use to describe very complex shapes. It is a lot like a coloring book, where coloring in each part of the page creates a picture. The Julia set is a way to show how you can start with something very simple - like a dot or a line - and then build up something complex and beautiful. To do this, mathematicians use computers to draw lots of dots, lines, and other shapes. By coloring in these shapes, the computer can draw all kinds of beautiful patterns. It's like a puzzle, but one that only a computer can solve.