grass

Grass is short plants with long narrow leaves that grow wild or in lawns.


Source
http://free-extras.com/images/field_of_grass-609.htm

graze

Graze is to eat in a field or pasture.


Source
http://boedeckers.com/images/GrazingGroup.jpg

herd

A herd is a large group of animals that live together.


Source
http://tjcnyc.files.wordpress.com/2008/08/herd.jpg

pattern

A pattern is anything characterized by repitition.