Software-based simulation of symbol replacement

1. A computer-implemented method involving a software application executed by a server machine on behalf of a client machine with a graphical display unit, wherein the software application involves graphically displaying, on vertical symbol display segments of the graphical display unit, animations that simulate spinning a plurality of reels, and wherein a memory of the server machine stores, for each reel of the plurality of reels, a respective plurality of symbols, subsets of which are displayable in a respective vertical symbol display segment corresponding to the reel, the computer-implemented method comprising:

selecting, by a processor of the server machine executing the software application, a first set of symbols, wherein the first set of symbols defines respective positions of each of the reels such that the first set of symbols is displayed on the vertical symbol display segments;

storing, by the processor, the first set of symbols in the memory;

causing the graphical display unit to display a first animation that simulates spinning of the reels, wherein spinning of the reels results in the vertical symbol display segments displaying the first set of symbols;

determining, by the processor, that the first set of symbols includes exactly one or exactly two trigger symbols, wherein only the first set of symbols including exactly one or exactly two trigger symbols causes the software application to replace the trigger symbols, and wherein the first set of symbols including three or more trigger symbols causes the software application to perform a payout based on the first set of symbols;

in response to determining that the first set of symbols includes exactly one or exactly two trigger symbols, replacing, by the processor, each of the trigger symbols with a wild symbol to form a second set of symbols, wherein the wild symbols are substitutable for any other symbol;

storing, by the processor, the second set of symbols in the memory;

determining that the second set of symbols contains one or more winning combinations;

in response to determining that the second set of symbols contains one or more winning combinations, performing an action based on the second set of symbols; and

causing the graphical display unit to display a second animation that simulates transformation of the trigger symbols into the wild symbols without spinning the reels.

2. The computer-implemented method of claim 1 , wherein causing the graphical display unit to display the first animation that simulates spinning of the reels comprises:

transmitting, by the processor, a representation of the first set of symbols to the client machine, wherein reception of the representation of the first set of symbols causes the client machine to display the first animation.

3. The computer-implemented method of claim 1 , wherein causing the graphical display unit to display the second animation that simulates transformation of the trigger symbols into the wild symbols without spinning the reels comprises:

transmitting, by the processor, a representation of the second set of symbols to the client machine, wherein reception of the representation of the second set of symbols causes the client machine to display the second animation.

4. The computer-implemented method of claim 1 , wherein the respective pluralities of symbols for the reels are arranged in respective cyclical sequences of symbols, and wherein determining the first set of symbols comprises:

for the reels, randomly selecting respective reel positions such that respective sub-sequences of the symbols thereon are in the first set of symbols.

5. The computer-implemented method of claim 1 , wherein the software application includes five reels and each of the five reels contributes three symbols to the first set of symbols and the second set of symbols.

6. The computer-implemented method of claim 1 , wherein the client machine is associated with a credit account, and wherein the credit account is debited to select the first set of symbols and credited based on patterns in the second set of symbols.

7. The computer-implemented method of claim 1 , wherein the processor simultaneously executes the software application in real time on behalf of at least 30 client machines, and wherein each of the at least 30 client machines communicates with the server machine by way of a wide area, packet-switched network.

8. A non-transitory computer-readable medium having stored thereon program instructions that define a software application, wherein the software application is executed by a server machine on behalf of a client machine with a graphical display unit, wherein the software application involves graphically displaying, on vertical symbol display segments of the graphical display unit, animations that simulate spinning a plurality of reels, wherein a memory of the server machine stores, for each reel of the plurality of reels, a respective plurality of symbols, subsets of which are displayable in a respective vertical symbol display segment corresponding to the reel, and wherein, upon execution by the server machine, the program instructions cause the server machine to perform operations comprising:

selecting, by a processor of the server machine executing the software application, a first set of symbols, wherein the first set of symbols defines respective positions of each of the reels such that the first set of symbols is displayed on the vertical symbol display segments;

storing, by the processor, the first set of symbols in the memory;

causing the graphical display unit to display a first animation that simulates spinning of the reels, wherein spinning of the reels results in the vertical symbol display segments displaying the first set of symbols;

determining, by the processor, that the first set of symbols includes exactly one or exactly two trigger symbols, wherein only the first set of symbols including exactly one or exactly two trigger symbols causes the software application to replace the trigger symbols, and wherein the first set of symbols including three or more trigger symbols causes the software application to perform a payout based on the first set of symbols;

in response to determining that the first set of symbols includes exactly one or exactly two trigger symbols, replacing, by the processor, each of the trigger symbols with a wild symbol to form a second set of symbols, wherein wild symbols are substitutable for any other symbol;

storing, by the processor, the second set of symbols in the memory;

determining that the second set of symbols contains one or more winning combinations;

in response to determining that the second set of symbols contains one or more winning combinations, performing an action based on the second set of symbols; and

causing the graphical display unit to display a second animation that simulates transformation of the trigger symbols into the wild symbols without spinning the reels.

9. The non-transitory computer-readable medium of claim 8 , wherein causing the graphical display unit to display the first animation that simulates spinning of the reels comprises:

transmitting, by the processor, a representation of the first set of symbols to the client machine, wherein reception of the representation of the first set of symbols causes the client machine to display the first animation.

10. The non-transitory computer-readable medium of claim 8 , wherein causing the graphical display unit to display the second animation that simulates transformation of the trigger symbols into the wild symbols without spinning the reels comprises:

transmitting, by the processor, a representation of the second set of symbols to the client machine, wherein reception of the representation of the second set of symbols causes the client machine to display the second animation.

11. The non-transitory computer-readable medium of claim 8 , wherein the respective pluralities of symbols for the reels are arranged in respective cyclical sequences of symbols, and wherein determining the first set of symbols comprises:

for the reels, randomly selecting respective reel positions such that respective sub-sequences of the symbols thereon are in the first set of symbols.

12. The non-transitory computer-readable medium of claim 8 , wherein the software application includes five reels and each of the five reels contributes three symbols to the first set of symbols and the second set of symbols.

13. The non-transitory computer-readable medium of claim 8 , wherein the client machine is associated with a credit account, and wherein the credit account is debited to select the first set of symbols and credited based on patterns in the second set of symbols.

14. A system configured for executing a software application, wherein the software application involves graphically displaying, on vertical symbol display segments, animations that simulate spinning a plurality of reels, and wherein the system stores, for each reel of the plurality of reels, a respective plurality of symbols, subsets of which are displayable in a respective vertical symbol display segment corresponding to the reel, the system comprising:

a client machine including a client machine processor, a client machine memory, a graphical display unit, and a plurality of input devices, wherein the plurality of input devices include: (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; and

program instructions executable to perform operations comprising:

selecting a first set of symbols, wherein the first set of symbols defines respective positions of each of the reels such that the first set of symbols is displayed on the vertical symbol display segments;

storing the first set of symbols;

causing the graphical display unit to display a first animation that simulates spinning of the reels, wherein spinning of the reels results in the vertical symbol display segments displaying the first set of symbols;

determining that the first set of symbols includes exactly one or exactly two trigger symbols, wherein only the first set of symbols including exactly one or exactly two trigger symbols causes the software application to replace the trigger symbols, and wherein the first set of symbols including three or more trigger symbols causes the software application to perform a payout based on the first set of symbols;

in response to determining that the first set of symbols includes exactly one or exactly two trigger symbols, replacing each of the trigger symbols with a wild symbol to form a second set of symbols, wherein wild symbols are substitutable for any other symbol;

storing the second set of symbols;

determining that the second set of symbols contains one or more winning combinations;

in response to determining that the second set of symbols contains one or more winning combinations, performing an action based on the second set of symbols; and

causing the graphical display unit to display a second animation that simulates transformation of the trigger symbols into the wild symbols without spinning the reels.

15. The system of claim 14 , wherein causing the graphical display unit to display the first animation that simulates spinning of the reels comprises:

transmitting a representation of the first set of symbols to the client machine, wherein reception of the representation of the first set of symbols causes the client machine to display the first animation.

16. The system of claim 14 , wherein causing the graphical display unit to display the second animation that simulates transformation of the trigger symbols into the wild symbols without spinning the reels comprises:

transmitting a representation of the second set of symbols to the client machine, wherein reception of the representation of the second set of symbols causes the client machine to display the second animation.

17. The system of claim 14 , wherein the respective pluralities of symbols for the reels are arranged in respective cyclical sequences of symbols, and wherein determining the first set of symbols comprises:

for the reels, randomly selecting respective reel positions such that respective sub-sequences of the symbols thereon are in the first set of symbols.

18. The system of claim 14 , wherein the software application includes five reels and each of the five reels contributes three symbols to the first set of symbols and the second set of symbols.

19. The system of claim 14 , wherein the client machine is associated with a credit account, and wherein the credit account is debited to select the first set of symbols and credited based on patterns in the second set of symbols.