Crown, headband, and spiral braids all start with a single braid and are worked around the head in a circular pattern. They can be done using any type of braid, with any number of strands.
Crown braids are a great way of dressing up your look with a comfortable style that will stay in all day. They work well with short hair as well as with longer hair.
For more pictures of crown braids I've done, see my Flickr set here.