Gaming machine with symbol locking

1. A computer-implemented method for symbol selection in a reel-based game, wherein the reel-based game is executed by a gaming machine on behalf of a client machine, wherein the reel-based game involves spinning a plurality of reels to determine outcome events, and a memory of the gaming machine stores respective pluralities of symbols for the reels, the method comprising:

selecting, by one or more processors of the gaming machine, a first set of symbols associated with respective positions of each of the reels, wherein the first set of symbols represents an outcome event of a base game of the reel-based game;

storing, by the one or more processors, the first set of symbols in the memory;

determining, by the one or more processors, that the outcome event includes a trigger event that causes execution of a bonus game, wherein the bonus game includes a predetermined number of bonus outcome events;

in response to determining that the outcome event includes the trigger event, selecting, by the one or more processors, a second set of symbols associated with respective positions of each of the reels as a bonus outcome event of the reel-based game;

storing, by the one or more processors, the second set of symbols in the memory;

determining that one or more pre-determined symbols in the second set of symbols are not part of any winning combination;

based on the one or more pre-determined symbols not being part of any winning combination, locking the one or more predetermined symbols that are not part of any winning combination, wherein locked predetermined symbols persist for at least one further bonus outcome event; and

selecting, by the one or more processors, a third set of symbols associated with the respective positions of each of the reels as a further bonus outcome event of the reel-based game, wherein the third set of symbols includes the locked predetermined symbols from the second set of symbols.

2. The method of claim 1 , wherein the predetermined symbol is a Wild symbol.

3. The method of claim 1 , wherein each reel comprises a respective cyclical sequence of symbols, and wherein selecting the first set of symbols, the second set of symbols, and the third set of symbols each comprise:

for each reel, randomly selecting a respective reel position that displays a subsequence of the symbols on the reel that are part of the first set of symbols, the second set of symbols, and the third set of symbols, respectively.

4. The method of claim 1 , wherein selecting the first set of symbols, the second set of symbols, and the third set of symbols each comprise:

simulating a respective spin of all reels.

5. The method of claim 1 , wherein both the base game and the bonus game have five reels and each of the five reels displays three symbols at a time.

6. The method of claim 1 , wherein the second set of symbols or the third set of symbols include a winning combination, the method further comprising:

determining a bonus payout amount associated with the second set of symbols or the third set of symbols; and

transmitting, to the client machine, an indication of the bonus payout amount.

7. The method of claim 6 , wherein the bonus payout amount is based on any predetermined symbols on the plurality of reels.

8. The method of claim 6 , wherein the client machine is associated with a credit account, and wherein the credit account is debited to play the base game, credited in response to the trigger event, and credited by the bonus payout amount.

9. The method of claim 1 , wherein the gaming machine simultaneously executes base games or bonus games in real time on behalf of at least 30 client machines, and wherein each of the at least 30 client machines communicates with the gaming machine by way of a wide-area packet-switched network.

10. The method of claim 1 , wherein the trigger event comprises the first set of symbols including at least n trigger symbols.

11. The method of claim 1 , wherein selecting each of the first set of symbols, the second set of symbols, and the third set of symbols comprises:

transmitting, to the client machine, a representation of the selected symbol set, wherein reception of the selected symbol set causes the client machine to display a spin of the plurality of reels resulting in the selected symbol set.

12. A gaming system configured for symbol replacement in a reel-based game, wherein the reel-based game is executed on behalf of a client machine, wherein the reel-based game involves spinning a plurality of reels to determine outcome events, the gaming system comprising:

a plurality of gaming devices each including at least one display device and a plurality of input devices including (i) an acceptor of a physical item associated with a monetary value, (ii) a validator configured to identify the physical item, and (iii) a cash-out button actuatable to cause an initiation of a payout associated with a credit account;

one or more gaming device processors; and

one or more gaming device memory devices storing (i) respective pluralities of symbols for the reels, including a predetermined symbol for the bonus game, and (ii) a plurality of gaming device instructions, the gaming device instructions executable by the one or more gaming device processors to perform operations comprising:

selecting a first set of symbols associated with respective positions of each of the reels, wherein the first set of symbols represents an outcome event of a base game of the reel-based game;

storing the first set of symbols in the one or more gaming device memory devices;

determining that the outcome event includes a trigger event that causes execution of a bonus game, wherein the bonus game includes a predetermined number of bonus outcome events;

in response to determining that the outcome event includes the trigger event, selecting a second set of symbols associated with respective positions of each of the reels as a bonus outcome event of the reel-based game;

storing the second set of symbols in the one or more gaming device memory devices;

determining that one or more pre-determined symbols in the second set of symbols are not part of any winning combination;

based on the one or more pre-determined symbols not being part of any winning combination, locking the one or more predetermined symbols that are not part of any winning combination, wherein locked predetermined symbols persist for at least one further bonus outcome event; and

selecting a third set of symbols associated with the respective positions of each of the reels as a further bonus outcome event of the reel-based game, wherein the third set of symbols includes the locked predetermined symbols from the second set of symbols.

13. A computer-implemented method comprising:

determining, by one or more processors of a gaming machine, that a trigger event for a bonus game occurred during a base outcome event of a base game, wherein the base game and the bonus game are both reel-based games being executed on behalf of a client machine, wherein both the base game and the bonus game involve spinning a plurality of reels, each reel containing a respective plurality of symbols, to determine outcome events, and wherein a memory of the gaming machine stores respective pluralities of symbols for the reels, including a predetermined symbol of the bonus game;

in response to determining that the trigger event occurred, awarding, by the one or more processors, a number of spins of the reels in an instance of the bonus game; and

until a terminating condition of the bonus game is reached, the one or more processors repeatedly carrying out iterations of bonus game operations comprising:

(i) selecting, from the stored pluralities of symbols for the reels, a symbol set for display on the plurality of reels, wherein the selected symbol set represents an outcome of a bonus game spin of the plurality of reels and includes any predetermined symbols still locked from a previous iteration of the bonus game,

(ii) determining whether one or more pre-determined symbols in the selected symbol set are part of any winning combination, wherein when the one or more predetermined symbols are not part of any winning combination, the one or more predetermined symbols are locked in place for at least one subsequent iteration of the bonus game in response to the one or more pre-determined symbols not being part of any winning combination, and wherein when the one or more locked predetermined symbols are part of a winning combination, the one or more locked predetermined symbols are unlocked in response to the one or more pre-determined symbols being part of the winning combination, and

(iii) transmitting, to the client machine, a representation of the selected symbol set, wherein reception of the selected symbol set causes the client machine to display the bonus game spin of the plurality of reels resulting in the selected symbol set.

14. The method of claim 13 , wherein the terminating condition includes where the awarded number of bonus game spins have been performed.

15. The method of claim 14 , wherein the terminating condition also includes where there are no locked predetermined symbols in the selected symbol set.

16. The method of claim 13 , wherein, after a locked predetermined symbol is unlocked, the unlocked predetermined symbol is replaced in a subsequent iteration of the bonus game.

17. The method of claim 16 , wherein when the selected symbol set includes no new predetermined symbols and does not include any winning combination, no symbols are locked or unlocked.

18. The method of claim 16 , wherein when the selected symbol set includes no new predetermined symbols and includes a winning combination, any locked predetermined symbols that are part of the winning combination are unlocked.

19. The method of claim 16 , wherein each reel comprises a respective cyclical sequence of symbols, and wherein selecting the symbol set for display on the plurality of reels comprises:

for each reel, randomly selecting a respective reel position that displays a subsequence of the symbols on the reel that are part of the selected symbol set.

20. The method of claim 16 , wherein, in an iteration of the bonus game in which a predetermined symbol is locked, causing the client machine to display the bonus game spin comprises:

causing the client machine to display an animated avatar interacting with the reels to lock the predetermined symbol.