Let's take a piece of graph paper. Now, graph paper is not what we normally think of as paper on which we render art, but I want to show you something, and you guessed it, it's regarding two dimensions. (Granted, graph paper particularly screams "two dimensions!")
Think about a repeating pattern of your own choice. It will wind up looking like a repeating pattern on a surface design, or on a piece of fabric. Connecting-tiles comes to mind, or even the lowly linoleum patterns. Design one pattern, or simply pick a very basic design like a music staff, or a simple logo that you are familiar with, or a triangle within a circle, or vice versa, etc.
Now decide how big a rectangle or square you want to use on your graph paper for this repeating design. For example a one-inch square, or a two-inch square, or a rectangle 1"by 2".
Soon you will see, with repeating your "design-logo" throughout the squares or the rectangles you have chosen, what your two-dimensional grid looks like, or your "linoleum," or your surface design on your fabric.