Take a circle.
Now take six other circles of the same size and surround that first circle. Now take six more circles and put one directly behind each those last six, making a hexagonal shape. You should now have three intersecting rows of five circles. Now, at the center of each circle, draw a line connecting it to every single circle, and then do the same for every other circle until all thirteen circles are connected. There should be a total of seventy-eight lines.
Now you have Metatron's Cube.
Metatron's Cube is a sacred geometry pattern used in the construction of religious structures and religious art, possibly derived from the Flower of Life pattern (a pattern composed of multiple overlapping circles whose end result looks like a bunch of flowers inside one large circle). Like the Flower of Life, it is considered to be a holy pattern and this one is named after the Metatron.
Here's a neat-o picture of an artist's rendering of one.