A gaming machine includes a display and a game controller that provides a wagering game in which a plurality of symbol display positions are provided on the display. When a player stakes a wager on the outcome of the wagering game the game controller selects symbols for display sequentially. The set of symbols is dynamic, wherein at least two symbols from the symbol set are changed between at least certain symbol selections depending on a characteristic of a symbol selected in a previous selection. The display positions may be arranged in rows and columns.