A pattern is simply a collection of pieces in some region of the board. The region may be near an edge, such as the Ziggurat
or it could be anywhere in the board, such as the basic bridge:
A pattern can be as large as you like -- for example here is a pattern: the only known single-stone 6th row edge template.
The starred hexes are not part of the pattern (they are only there because no-one has taken the trouble to find out how to remove them).