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 carrier of a pattern is the set of all cells that are part of the pattern (whether occupied by pieces or not).