 I want to tell you about crystals. You might be surprised to know that a crystal isn't an expensive piece of glass or a chandelier in some fancy dining room. The word crystal simply means a pattern that is periodic. Look at this checkerboard pattern. See how it continues to spread out infinitely in each direction? That means it's a periodic pattern. So that's a two-dimensional crystal. This is another two-dimensional crystal. And this is another. You can also have three-dimensional crystals. By the way, this 3D glass is called crystal because its atoms are actually arranged in a crystalline pattern. So, see how I'm projecting this three-dimensional crystal to a two-dimensional image on the sand? See how the 2D projection looks distorted because of the angle of the projection? That 2D image also has a pattern. But it isn't periodic. So, it's not a crystal. But there's a deep connection between the 2D object on the sand and the 3D mother crystal. This distorted 2D pattern is called a quasi-crystal. A quasi-crystal in a certain dimension, in this case 2D, is a projection of a crystal in a higher dimension, in this case 3D. A group of physicists in Los Angeles is working on a new physics theory, or a particular 8D crystal. Yup, that's right. An eight-dimensional crystal is projected to 4D at a very particular angle, which forms a 4D quasi-crystal. And from this 4D quasi-crystal, they derive a 3D quasi-crystal, which they believe is the fundamental substructure of all of reality.