Gaming systems and methods using dynamic modifiers

1. A gaming system comprising:

a gaming machine comprising a display device configured to display a symbol array comprising a plurality of symbols and a modifier array comprising a plurality of modifiers; and

game-logic circuitry is configured to:

select, for a plurality of rounds of populating the symbol array with symbols, a subarray of the modifier array, the selected subarray displayed by the display device;

generate, using a random-number generator of the game-logic circuitry, one or more random numbers to determine an outcome of a round of the plurality of rounds;

in response to the outcome of the round including an expansion symbol, cause the display device to expand the subarray to include at least one additional array position of the modifier array;

in response to the outcome of the round including a shift symbol, cause the display device to shift the selected subarray by at least one array position of the modifier array; and

in response to a trigger round of the plurality of rounds, cause the display device to apply the modifiers of the subarray to an outcome associated with the trigger round.

2. The gaming system of claim 1 , wherein a number of rows or a number of columns of the symbol array expands to match a number of array positions of the selected subarray when the outcome of the round includes the shift symbol.

3. The gaming system of claim 1 , wherein a first modifier of the plurality of modifiers is presented by the display device outside of the selected subarray prior to the outcome of the round including the shift symbol, and wherein the display device presents the first modifier within the selected subarray in response to the shift symbol causing the first modifier to shift within the selected subarray.

4. The gaming system of claim 1 , wherein the trigger round is a final round of the plurality of rounds.

5. The gaming system of claim 4 , wherein a new subarray is selected from the modifier array in response to the outcome associated with the trigger round.

6. The gaming system of claim 1 , wherein the plurality of modifiers includes a wild symbol modifier to replace a symbol populating the symbol array with a wild symbol.

7. The gaming system of claim 1 , wherein the plurality of modifiers includes a multiplier modifier for increasing an award for a winning outcome.

8. The gaming system of claim 1 , wherein the plurality of modifiers includes a blank that does not apply any modifier or change when the modifiers of the subarray are applied to an outcome associated with the trigger round.

9. The gaming system of claim 1 , wherein the display device is configured to display the modifier array as a symbol-bearing reel.

10. The gaming system of claim 1 , wherein the display device is configured to display the modifier array as a wheel.

11. A method of using a gaming system comprising game-logic circuitry and a gaming machine, the gaming machine having a display device in communication with the game-logic circuitry, the method comprising:

displaying, via the display device, a symbol array comprising a plurality of symbols and a modifier array comprising a plurality of modifiers;

selecting, by the game-logic circuitry and for a plurality of rounds of populating the symbol array with symbols, a subarray of the modifier array, the selected subarray displayed by the display device;

generating, using a random-number generator of the game-logic circuitry, one or more random numbers to determine an outcome of a round of the plurality of rounds;

in response to the outcome of the round including an expansion symbol, causing, by the game-logic circuitry, the display device to expand the subarray to include at least one additional array position of the modifier array;

in response to the outcome of the round including a shift symbol, cause the display device to shift the selected subarray by at least one array position of the modifier array; and

in response to a trigger round of the plurality of rounds, causing, by the game-logic circuitry, the display device to apply the modifiers of the subarray to an outcome associated with the trigger round.

12. The method of claim 11 , wherein a number of rows or a number of columns of the symbol array expands to match a number of array positions of the selected subarray when the outcome of the round includes the shift symbol.

13. The method of claim 11 , wherein a first modifier of the plurality of modifiers is presented by the display device outside of the selected subarray prior to the outcome of the round including the shift symbol, and wherein the display device presents the first modifier within the selected subarray in response to the shift symbol causing the first modifier to shift within the selected subarray.

14. The method of claim 11 , wherein the trigger round is a final round of the plurality of rounds.

15. The method of claim 14 , wherein a new subarray is selected from the modifier array in response to the outcome associated with the trigger round.

16. The method of claim 11 , wherein the plurality of modifiers includes a wild symbol modifier to replace a symbol populating the symbol array with a wild symbol.

17. The method of claim 11 , wherein the plurality of modifiers includes a multiplier modifier for increasing an award for a winning outcome.

18. The method of claim 11 , wherein the plurality of modifiers includes a blank that does not apply any modifier or change when the modifiers of the subarray are applied to an outcome associated with the trigger round.

19. The method of claim 11 , wherein the modifier array is displayed as a symbol-bearing reel.

20. The method of claim 11 , wherein the modifier array is displayed as a wheel.