Pattern

A pattern is anything characterized by repetition. The repetition can either have identical subpatterns or subpatterns that are modified according to some simple rule.

Generally speaking, patterns can be detected or recognized by people (or in some cases, by computers).

Patterns may be observable through the senses.

Some patterns are named. Examples include the regular tiling of a plane, echoes, and balanced binary branching.

Fractals are mathematical patterns. Naturally occuring patterns obey certain principles also found in fractals, for example self-similarity. Even though self-similarity in nature is only approximate and stochastic, integral measures describing fractal properties can also be applied to natural "fractals" like coastal lines, tree shapes, etc. (see fractal geometry). While the outer appearance of self-similar patterns can be quite complex, the rules needed to describe or produce their formation can be extremely simple (e.g. Lindenmayer systems for the description of tree shapes).

In addition to static patterns there may be patterns of movement such as oscillation.

Patterns In Nature

• Sea shells, Sand Dollars, etc.
• Sand dunes, Grand Canyon, etc.
• Tree branches, ferns, coastal lines, clouds, etc.

• Modern art: Mondrian, Op Art
• Impressionism: Pointillism
• Performance Art: Crop circles

• Fractals
• Crystals
• Penrose tilings

• often "pattern" means a template, or a cookie cutter-like template. See, e.g. design pattern (architecture) and design pattern (computer science).

• Pattern recognition
• Regular expressions
• DNA motifs