A pattern is a regularity in the world, in human-made design, or in
abstract ideas. As such, the elements of a pattern repeat in a predictable
manner. A geometric pattern is a kind of pattern formed of geometric
shapes and typically repeated like a wallpaper design.
Any of the senses may directly observe patterns. Conversely, abstract patterns
in science, mathematics, or language may be observable only by analysis.
Direct observation in practice means seeing visual patterns, which are
widespread in nature and in art. Visual patterns in nature are often chaotic,
rarely exactly repeating, and often involve fractals. Natural patterns include
spirals, meanders, waves, foams, tilings, cracks, and those created by
symmetries of rotation and reflection.