Definition: Decorative design as executed on carpet, wallpaper, cloth etc., on target: ~welding, welding of alternate strips of of twisted or plaited iron and steel producing a pattern.
Patterns may be directly observed with any of our five senses.
Visual patterns are very common such as simple decorative patterns (stripes, zigzags, and polka-dots). Others can be more complicated, however, they may be found anywhere in nature and in art.
A recurring pattern in a piece of art is referred to as a motif.
The golden ratio (approximately 1.618) is found frequently in nature. It is defined by two numbers, that form a ratio such that (a+b)/a = a/b (a/b being the golden ratio). This pattern was exploited by Leonardo da Vinci in his art. The golden ratio can be seen in nature, from the spirals of flowers to the symmetry of the human body (as expressed in Da Vinci's Vitruvian Man, one of the most referenced and reproduced works of art today. This is still used by many artists).
"Art is the imposing of a pattern on experience, and our aesthetic enjoyment is recognition of the pattern."
Alfred North Whitehead (1861-1947), English philosopher and mathematician. Dialogues, June 10, 1943.