Mathematics can be defined as the study of abstract patterns. Numbers, of course, are one of the first examples of an abstraction: two plus three is five, whether we're adding apples, or oranges, or something abstract like ideas.  But for mathematicians, patterns of even greater abstraction are found all around us.

 Symmetries form another familiar example of patterns.  The human visual system is especially sensitive to vertical mirror symmetry, as found (approximately) in the faces and bodies of most animals.