I see pattern as a representation of repetition and duplication. It can be seen to the eye as recognizable, and it is seen in many aspects of everyday life, from geography to clothing.
The Washington State University tartan is a great representation of pattern in a very obvious way. It has basic cross patterns with the lines that move through the surface. The colors of each line that intersect create the even square patterns throughout.
This image displays multiple observations of pattern. The duplication of the benches create repetition where a pattern emerges. Even though it is not perfect spacing, you can see the idea of them lines up creates a compositional pattern in the physical space. Brick is also a basic and well known form of pattern because of its repetition and spacing. The rows that alternate are one of the most well known patterns to the eye and it is very easy to see it.
We see patterns in fashion all the time. This image I took of a model represents a chaotic pattern in the flower button up he is wearing. Even though there is not immediate pattern seen like on the tartan, the repetition of the flower shapes and colors make a pattern. The snake patch on his Gucci jeans represents a pattern as well, since it is seen in many other Gucci products. It is repeated in the brand, and is one of their recent trademarks.