Described herein is a gaming machine and, a method of gaming thereon, comprising: a symbol selector for selecting a plurality of symbols from a set of symbols during play of a game, the set of symbols including a plurality of function symbols; a display having at least a game area, the selected symbols being displayed in said game area; an outcome evaluator for determining that at least one predefined triggering criterion is satisfied; and a game area expander for expanding said game area in response to said at least one predefined triggering criterion being satisfied, such that at least one additional symbol of the set of symbols is displayed in an expanded game area.