Patterns

Something is asymmetric if it not symmetric. If something is asymmetric, if you cut it in half, the two sides will not be mirror images of each other.

A blotch is a large, irregular spot on something. The leaf in the picture is blotchy.

A group of things are concentric if they all have the same center. The circles in the picture all have the same central point. Any shape can be concentric - triangles, squares, or even three dimensional shapes like spheres.

Something is spotted if it has a pattern of small, round things all over it. Many animals are spotted. If the spots are perfectly round and even they are usually called dots. People will usually call animals covered in dots spotted and clothes covered in spots to be dotted.

A fleck is a small piece of something, like a fleck of dirt.
Something that has a lot of flecks on it is called flecked.

A formation is an arrangement of things, or how something has been formed. You might talk about a rock formation, a cloud formation, or aircraft flying in formation.

Grain is a word used to describe the direction of the fibers or layers inside a natural material like wood or stone. Materials with a grain are very easy to split along the direction of the grain, and they are naturally stronger if the grain is run lengthways along a piece of that material.
Anything else that has a distinct direction in what it is made from can also be described as having a grain, such as the direction of fur on an animal's hide.

Herringbone is a pattern with a distinctive zigzag in it. It can be seen on tweed clothes, knitted clothes and also as a floor design.

A lattice is made from strips of a material like wood crossing over itself, leaving gaps between the strips. The gaps are usually square or diamond shaped, but more intricate lattices have more interesting shapes. Lattices can be made from wood, plastic, metal or may even be made out of pastry strips on top of a pie.

Paisley is a pattern based around twisted teadrop shapes.