Patent Publication Number: US-8986102-B2

Title: Wagering game with ascending features

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application claims the benefit of U.S. Provisional Patent Application 61/740,743, filed on Dec. 21, 2012, which is hereby incorporated by reference in its entirety. 
    
    
     COPYRIGHT 
     A portion of the disclosure of this patent document contains material which is subject to copyright protection. The copyright owner has no objection to the facsimile reproduction by anyone of the patent disclosure, as it appears in the Patent and Trademark Office patent files or records, but otherwise reserves all copyright rights whatsoever. 
     FIELD OF THE INVENTION 
     The present invention relates generally to gaming apparatus and methods and, more particularly, to a method and system of conducting a wagering game on a wagering game machine such that a game outcome triggers an ascending feature resulting in changes to displayed game symbols. 
     BACKGROUND OF THE INVENTION 
     Gaming machines, such as slot machines, video poker machines and the like, have been a cornerstone of the gaming industry for several years. Generally, the popularity of such machines with players is dependent on the likelihood (or perceived likelihood) of winning money at the machine and the intrinsic entertainment value of the machine relative to other available gaming options. Where the available gaming options include a number of competing machines and the expectation of winning at each machine is roughly the same (or believed to be the same), players are likely to be attracted to the most entertaining and exciting machines. Shrewd operators consequently strive to employ the most entertaining and exciting machines, features, and enhancements available because such machines attract frequent play and hence increase profitability to the operator. Therefore, there is a continuing need for gaming machine manufacturers to continuously develop new games and improved gaming enhancements that will attract frequent play through enhanced entertainment value to the player. 
     One concept that has been successfully employed is a game feature or bonus feature that is triggered by an event occurring in a “basic” game. The game feature may include any type of modification or enhancement to game play of the basic game. The triggering event is pre-selected to initiate the game feature and may be known or unknown to the player. An unknown triggering event, or “mystery trigger,” may be linked to a recognizable game event, such as a winning outcome or a non-winning outcome, and may occur randomly throughout the basic game. 
     Game and bonus features may operate in conjunction with basic game play, may modify and/or enhance basic game play, and may be dissimilar to basic game play with regards to game mechanics, game play experience, and other characteristics. Popular game and bonus features include free spins, award multipliers, and special awards and symbols, but game and bonus features may take any form. Often, game and bonus features provide a player an opportunity to obtain more and higher-value awards than are typically achieved in basic game play, and so provide incentive to play the wagering game in which they appear. 
     SUMMARY OF THE INVENTION 
     According to one aspect of the present invention, a gaming system is configured to conduct a wagering game. The wagering game includes a game outcome that is randomly selected from a plurality of game outcomes including at least one ascending-feature outcome. The gaming system includes one or more input devices, one or more display devices, one or more processors, and one or more memory storage devices. The one or more memory storage devices store instructions that, when executed by the one or more processors, cause the gaming system to receive an input indicative of a wager initiating the wagering game, randomly select a game outcome of the plurality of game outcomes, and display at least a portion of the selected game outcome as an array of game symbols. In direct response to the selected game outcome being one of the at least one ascending-feature outcome, the instructions cause the gaming system to select a first set of game symbols from the array according to first criteria and modify the array by changing the selected first set into symbols having a higher value than the first set. Also, in direct response to the modified array resulting in at least one winning combination of symbols being displayed, the gaming system awards a player any awards associated with the at least one winning combination. In direct response to the modified array not resulting in a winning combination, the gaming system selects a second set of displayed game symbols from the modified array according to second criteria and further modifies the modified array by changing the selected second set into symbols having a higher value than the second set. 
     According to another embodiment of the invention, a computer-implemented method conducts a wagering game on a gaming system including one or more input devices, one or more display devices, and one or more processors. The wagering game includes randomly selecting a game outcome from a plurality of game outcomes including at least one ascending-feature outcome. The method comprises receiving, via at least one of the one or more input devices, an input indicative of a wager initiating the wagering game. The method further randomly selects, via at least one of the one or more processors, a game outcome of the plurality of game outcomes and displays, via at least one of the one or more display devices, at least a portion of the selected game outcome as an array of game symbols. In direct response to the selected game outcome being one of the at least one ascending-feature outcome, the method selects, via at least one of the one or more processors, at least one of a first set of game symbols from the array according to a first criteria and modifies the array by changing the at least one of the first set into a symbol having a higher value than the at least one symbol of the first set. Also, in direct response to the modified array resulting in at least one winning combination of symbols being displayed, the method awards a player any awards associated with the at least one winning combination. In direct response to the modified array not resulting in a winning combination, the method selects, via at least one of the one or more processors, at least one of a second set of the displayed game symbols from the modified array according to second criteria and further modifies the modified array by changing the at least one symbol of the second set into a symbol having a higher value than the at least one symbol of the second set. 
     According to a different aspect of the invention, a gaming system is configured to conduct a wagering game including randomly selecting a game outcome from a plurality of game outcomes. The gaming system includes one or more input devices, one or more display devices, one or more processors, and one or more memory storage devices. The one or more memory storage devices storing instructions that, when executed by at least one of the one or more processors, cause the gaming system to receive, via at least one of the one or more input devices, an input indicative of a first wager initiating the wagering game. The instructions further cause the gaming system to randomly select a game outcome of the plurality of game outcomes and display, via at least one of the one or more display devices, at least a portion of the selected game outcome as an array of game symbols. In direct response to the displayed array including a full column of wild symbols that is not the leftmost column of the array, the gaming system awards the player any awards associated with the selected game outcome, and changes the column that is left-adjacent to the full column into wild symbols for displaying in a next-subsequent game outcome. The instructions further cause the gaming system to receive, via at least one of the one or more input devices, an input indicative of a second wager. The gaming system randomly selects a next-subsequent game outcome of the plurality of game outcomes and displays, via at least one of the one or more display devices, at least a portion of the next-subsequent game outcome as a new array of game symbols including the left-adjacent column of wild symbols. 
     According to yet another aspect of the invention, computer-readable storage media includes executable instructions that, when executed by at least one of one or more processors, cause a gaming system including one or more input devices and one or more display devices, to perform a method comprising receiving, via at least one of the one or more input devices, an input indicative of a wager initiating a wagering game. The instructions cause the gaming system to randomly select a game outcome of a plurality of game outcomes including at least one ascending-feature outcome and display at least a portion of the selected game outcome as an array of game symbols. In direct response to the selected game outcome being one of the at least one ascending-feature outcome, the gaming system selects a first set of game symbols from the array according to first criteria and modifies the array by changing the selected first set into symbol having a higher value than the first set. In direct response to the modified array resulting in at least one winning combination of symbols being displayed, the gaming system awards a player any awards associated with the at least one winning combination. Also, in direct response to the modified array not resulting in a winning combination, the gaming system selects a second set of displayed game symbols from the modified array according to second criteria and further modifies the modified array by changing the selected second set into symbols having a higher value than the second set. 
     Additional aspects of the invention will be apparent to those of ordinary skill in the art in view of the detailed description of various embodiments, which is made with reference to the drawings, a brief description of which is provided below. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a perspective view of a free-standing gaming terminal according to an embodiment of the present invention. 
         FIG. 2  is a schematic view of a gaming system according to an embodiment of the present invention. 
         FIG. 3  is an image of an exemplary basic-game screen of a wagering game displayed on a gaming terminal, according to an embodiment of the present invention. 
         FIG. 4  presents a basic-game screen of an embodiment of the present invention. 
         FIG. 5  presents another game screen of an embodiment of the present invention, in which a game symbol has been changed into a higher-value symbol. 
         FIG. 6  presents another game screen of an embodiment of the present invention, in which a second game symbol has been changed into a higher-value symbol. 
         FIG. 7  presents another game screen of an embodiment of the present invention, in which three game symbols have been changed into higher-value symbols. 
         FIG. 8  presents another game screen of an embodiment of the present invention, in which two least-valuable game symbols have been changed into higher-value symbols. 
         FIG. 9  presents another game screen of an embodiment of the present invention, in which more game symbols have been changed into higher-value symbols. 
         FIG. 10  is an image of a basic-game screen of an embodiment of the present invention, in which a full column of WILD symbols is displayed. 
         FIG. 11  presents another game screen of the embodiment of  FIG. 10 , in which the column left-adjacent to the previous full column of WILD symbols has been changed into a full column of WILD symbols. 
         FIG. 12  is an image of a bonus-game screen of an embodiment of the present invention presents another game screen of an embodiment of the present invention, in which a full column of WILD symbols is displayed. 
         FIG. 13  presents another game screen of the embodiment of  FIG. 12 , in which the WILD symbols have dropped down one position in the column. 
         FIG. 14  is a flowchart for an algorithm that corresponds to instructions executed by one or more processors in accord with at least some aspects of the disclosed concepts. 
     
    
    
     While the invention is susceptible to various modifications and alternative forms, specific embodiments have been shown by way of example in the drawings and will be described in detail herein. It should be understood, however, that the invention is not intended to be limited to the particular forms disclosed. Rather, the invention is to cover all modifications, equivalents, and alternatives falling within the spirit and scope of the invention as defined by the appended claims. 
     DETAILED DESCRIPTION 
     While this invention is susceptible of embodiment in many different forms, there is shown in the drawings and will herein be described in detail preferred embodiments of the invention with the understanding that the present disclosure is to be considered as an exemplification of the principles of the invention and is not intended to limit the broad aspect of the invention to the embodiments illustrated. For purposes of the present detailed description, the singular includes the plural and vice versa (unless specifically disclaimed); the words “and” and “or” shall be both conjunctive and disjunctive; the word “all” means “any and all”; the word “any” means “any and all”; and the word “including” means “including without limitation.” 
     For purposes of the present detailed description, the terms “wagering games,” “gambling,” “slot game,” “casino game,” and the like include games in which a player places at risk a sum of money or other representation of value, whether or not redeemable for cash, on an event with an uncertain outcome, including without limitation those having some element of skill. In some embodiments, the wagering game may involve wagers of real money, as found with typical land-based or on-line casino games. In other embodiments, the wagering game may additionally, or alternatively, involve wagers of non-cash values, such as virtual currency, and therefore may be considered a social or casual game, such as would be typically available on a social networking web site, other web sites, across computer networks, or applications on mobile devices (e.g., phones, tablets, etc.). When provided in a social or casual game format, the wagering game may closely resemble a traditional casino game, or it may take another form that more closely resembles other types of social/casual games. 
     Referring to  FIG. 1 , there is shown a gaming terminal  10  similar to those used in gaming establishments, such as casinos. With regard to the present invention, the gaming terminal  10  may be any type of gaming terminal and may have varying structures and methods of operation. For example, in some aspects, the gaming terminal  10  is an electromechanical gaming terminal configured to play mechanical slots, whereas in other aspects, the gaming terminal is an electronic gaming terminal configured to play a video casino game, such as slots, keno, poker, blackjack, roulette, craps, etc. The gaming terminal  10  may take any suitable form, such as floor-standing models as shown, handheld mobile units, bartop models, workstation-type console models, etc. Further, the gaming terminal  10  may be primarily dedicated for use in conducting wagering games, or may include non-dedicated devices, such as mobile phones, personal digital assistants, personal computers, etc. Exemplary types of gaming terminals are disclosed in U.S. Pat. No. 6,517,433 and Patent Application Publication Nos. US2010/0069160 and US2010/0234099, which are incorporated herein by reference in their entireties. 
     The gaming terminal  10  illustrated in  FIG. 1  comprises a cabinet  11  that may house various input devices, output devices, and input/output devices. By way of example, the gaming terminal  10  includes a primary display area  12 , a secondary display area  14 , and one or more audio speakers  16 . The primary display area  12  or the secondary display area  14  may be a mechanical-reel display, a video display, or a combination thereof in which a transmissive video display is disposed in front of the mechanical-reel display to portray a video image superimposed upon the mechanical-reel display. The display areas may variously display information associated with wagering games, non-wagering games, community games, progressives, advertisements, services, premium entertainment, text messaging, emails, alerts, announcements, broadcast information, subscription information, etc. appropriate to the particular mode(s) of operation of the gaming terminal  10 . The gaming terminal  10  includes a touch screen(s)  18  mounted over the primary or secondary areas, buttons  20  on a button panel, bill validator  22 , information reader/writer(s)  24 , and player-accessible port(s)  26  (e.g., audio output jack for headphones, video headset jack, USB port, wireless transmitter/receiver, etc.). It should be understood that numerous other peripheral devices and other elements exist and are readily utilizable in any number of combinations to create various forms of a gaming terminal in accord with the present concepts. 
     Input devices, such as the touch screen  18 , buttons  20 , a mouse, a joystick, a gesture-sensing device, a voice-recognition device, and a virtual input device, accept player input(s) and transform the player input(s) to electronic data signals indicative of the player input(s), which correspond to an enabled feature for such input(s) at a time of activation (e.g., pressing a “Max Bet” button or soft key to indicate a player&#39;s desire to place a maximum wager to play the wagering game). The input(s), once transformed into electronic data signals, are output to a CPU for processing. The electronic data signals are selected from a group consisting essentially of an electrical current, an electrical voltage, an electrical charge, an optical signal, an optical element, a magnetic signal, and a magnetic element. 
     Turning now to  FIG. 2 , there is shown a block diagram of the gaming-terminal architecture. The gaming terminal  10  includes a central processing unit (CPU)  30  connected to a main memory  32 . The CPU  30  may include any suitable processor(s), such as those made by Intel and AMD. By way of example, the CPU  30  includes a plurality of microprocessors including a master processor, a slave processor, and a secondary or parallel processor. CPU  30 , as used herein, comprises any combination of hardware, software, or firmware disposed in or outside of the gaming terminal  10  that is configured to communicate with or control the transfer of data between the gaming terminal  10  and a bus, another computer, processor, device, service, or network. The CPU  30  comprises one or more controllers or processors and such one or more controllers or processors need not be disposed proximal to one another and may be located in different devices or in different locations. The CPU  30  is operable to execute all of the various gaming methods and other processes disclosed herein. The main memory  32  includes a wagering game unit  34 . In one embodiment, the wagering game unit  34  may present wagering games, such as video poker, video black jack, video slots, video lottery, etc., in whole or part. 
     The CPU  30  is also connected to an input/output (I/O) bus  36 , which can include any suitable bus technologies, such as an AGTL+ frontside bus and a PCI backside bus. The I/O bus  36  is connected to various input devices  38 , output devices  40 , and input/output devices  42  such as those discussed above in connection with  FIG. 1 . The I/O bus  36  is also connected to storage unit  44  and external system interface  46 , which is connected to external system(s)  48  (e.g., wagering game networks). 
     The external system  48  includes, in various aspects, a gaming network, other gaming terminals, a gaming server, a remote controller, communications hardware, or a variety of other interfaced systems or components, in any combination. In yet other aspects, the external system  48  may comprise a player&#39;s portable electronic device (e.g., cellular phone, electronic wallet, etc.) and the external system interface  46  is configured to facilitate wireless communication and data transfer between the portable electronic device and the CPU  30 , such as by a near-field communication path operating via magnetic-field induction or a frequency-hopping spread spectrum RF signals (e.g., Bluetooth, etc.). 
     The gaming terminal  10  optionally communicates with the external system  48  such that the terminal operates as a thin, thick, or intermediate client. In general, a wagering game includes an RNG for generating a random number, game logic for determining the outcome based on the randomly generated number, and game assets (e.g., art, sound, etc.) for presenting the determined outcome to a player in an audio-visual manner. The RNG, game logic, and game assets are contained within the gaming terminal  10  (“thick client” gaming terminal), the external system  48  (“thin client” gaming terminal), or are distributed therebetween in any suitable manner (“intermediate client” gaming terminal). 
     The gaming terminal  10  may include additional peripheral devices or more than one of each component shown in  FIG. 2 . Any component of the gaming terminal architecture may include hardware, firmware, or tangible machine-readable storage media including instructions for performing the operations described herein. Machine-readable storage media includes any mechanism that stores information and provides the information in a form readable by a machine (e.g., gaming terminal, computer, etc.). For example, machine-readable storage media includes read only memory (ROM), random access memory (RAM), magnetic disk storage media, optical storage media, flash memory, etc. 
     Referring now to  FIG. 3 , there is illustrated an image of a basic-game screen  50  adapted to be displayed on the primary display area  12  or the secondary display area  14 . The basic-game screen  50  portrays a plurality of simulated symbol-bearing reels  52 . Alternatively or additionally, the basic-game screen  50  portrays a plurality of mechanical reels or other video or mechanical presentation consistent with the game format and theme. The basic-game screen  50  also advantageously displays one or more game-session credit meters  54  and various touch screen buttons  56  adapted to be actuated by a player. A player can operate or interact with the wagering game using these touch screen buttons or other input devices such as the buttons  20  shown in  FIG. 1 . The CPU operate(s) to execute a wagering game program causing the primary display area  12  or the secondary display area  14  to display the wagering game. 
     In response to receiving an input indicative of a wager, the reels  52  are rotated and stopped to place symbols on the reels in visual association with paylines such as paylines  58 . The wagering game evaluates the displayed array of symbols on the stopped reels and provides immediate awards and bonus features in accordance with a pay table. The pay table may, for example, include “line pays” or “scatter pays.” Line pays occur when a predetermined type and number of symbols appear along an activated payline, typically in a particular order such as left to right, right to left, top to bottom, bottom to top, etc. Scatter pays occur when a predetermined type and number of symbols appear anywhere in the displayed array without regard to position or paylines. Similarly, the wagering game may trigger bonus features based on one or more bonus triggering symbols appearing along an activated payline (i.e., “line trigger”) or anywhere in the displayed array (i.e., “scatter trigger”). The wagering game may also provide mystery awards and features independent of the symbols appearing in the displayed array. 
     In accord with various methods of conducting a wagering game on a gaming system in accord with the present concepts, the wagering game includes a game sequence in which a player makes a wager and a wagering game outcome is provided or displayed in response to the wager being received or detected. The wagering game outcome is then revealed to the player in due course following initiation of the wagering game. The method comprises the acts of conducting the wagering game using a gaming apparatus, such as the gaming terminal  10  depicted in  FIG. 1 , following receipt of an input from the player to initiate the wagering game. The gaming terminal  10  then communicates the wagering game outcome to the player via one or more output devices (e.g., primary display  12  or secondary display  14 ) through the display of information such as, but not limited to, text, graphics, static images, moving images, etc., or any combination thereof. In accord with the method of conducting the wagering game, the CPU transforms a physical player input, such as a player&#39;s pressing of a “Spin Reels” touch key, into an electronic data signal indicative of an instruction relating to the wagering game (e.g., an electronic data signal bearing data on a wager amount). 
     In the aforementioned method, for each data signal, the CPU (e.g., CPU  30 ) is configured to process the electronic data signal, to interpret the data signal (e.g., data signals corresponding to a wager input), and to cause further actions associated with the interpretation of the signal in accord with computer instructions relating to such further actions executed by the controller. As one example, the CPU causes the recording of a digital representation of the wager in one or more storage media (e.g., storage unit  44 ), the CPU, in accord with associated computer instructions, causing the changing of a state of the storage media from a first state to a second state. This change in state is, for example, effected by changing a magnetization pattern on a magnetically coated surface of a magnetic storage media or changing a magnetic state of a ferromagnetic surface of a magneto-optical disc storage media, a change in state of transistors or capacitors in a volatile or a non-volatile semiconductor memory (e.g., DRAM), etc. The noted second state of the data storage media comprises storage in the storage media of data representing the electronic data signal from the CPU (e.g., the wager in the present example). As another example, the CPU further, in accord with the execution of the instructions relating to the wagering game, causes the primary display  12 , other display device, or other output device (e.g., speakers, lights, communication device, etc.) to change from a first state to at least a second state, wherein the second state of the primary display comprises a visual representation of the physical player input (e.g., an acknowledgement to a player), information relating to the physical player input (e.g., an indication of the wager amount), a game sequence, an outcome of the game sequence, or any combination thereof, wherein the game sequence in accord with the present concepts comprises acts described herein. The aforementioned executing of computer instructions relating to the wagering game is further conducted in accord with a random outcome (e.g., determined by a RNG) that is used by the CPU to determine the outcome of the game sequence, using a game logic for determining the outcome based on the randomly generated number. In at least some aspects, the CPU is configured to determine an outcome of the game sequence at least partially in response to the random parameter. 
     Referring now to  FIG. 4 , there is shown a basic-game screen  450  showing a plurality of simulated symbol-bearing reels  452 , game session credit meters  454 , and touch screen buttons  456 . The symbol-bearing reels  452  present an array of game symbols, such as the symbols  442 , that represent the game outcome determined by game logic and based on a randomly generated number. As previously described, at least one of the one or more processors of a gaming terminal such as the gaming terminal  10  execute the game logic after receipt of an input indicating a player has made a wager to initiate the wagering game. 
     In an embodiment of the invention, the randomly selected game outcome includes an ascending-feature outcome, as determined by the game logic. At least a portion of the selected game outcome is displayed in the array of  FIG. 4 . The ascending-feature outcome of this embodiment does not include a winning symbol combination indicated on the wagering game&#39;s paytable, and does not include a symbol or symbol combination that is identified to the player as the ascending-feature outcome. Other embodiments may include an ascending-feature outcome that includes a winning symbol combination, as well as an ascending-feature outcome that is identified to the player either before, during, or after displaying the ascending-feature outcome in the array. 
     The occurrence of the ascending-feature outcome may automatically trigger a game feature in which a first set of game symbols is selected from the symbols displayed in the array and changed into one or more higher-value symbols. The first set of game symbols may be selected according to first criteria included in the game logic or determined by the game logic during the course of the wagering game. In  FIG. 4 , the first criteria include selecting a symbol from the rightmost column  452  (column  5 ) of the array, and in this case the wagering game selects the dagger symbol  442  to be the only symbol in the first set of symbols. 
     Referring now to  FIG. 5 , the dagger symbol of the first set has been changed to a higher-value symbol (i.e., the WILD symbol  542 ) which may substitute for other symbols on the symbol-bearing reels  552 . The array is evaluated for winning combinations resulting from the newly added WILD symbol  542  and, if the array includes a winning combination, the feature may terminate and return to the basic game. 
     In  FIG. 5 , the array (including the new WILD symbol  542 ) does not include a winning symbol combination, and so the wagering game selects, according to second criteria, a second set of game symbols to be changed into higher-value symbols. In this case, the second criteria includes selecting a symbol from the next-to-rightmost column, and in  FIG. 6  the wagering game has selected and changed the middle symbol of the column  652  (column  4 ) into another WILD symbol  642 . The array is evaluated again for winning symbol combinations resulting from the newly added WILD symbol  642  and, once again, the array does not include a winning symbol combination. 
     In the absence of a winning combination after selecting and changing the first and second sets of symbols, the wagering game may select third set of symbols according to third criteria and change the third set to a higher-value symbol. As shown in  FIG. 7 , the third criteria includes selecting a symbol from the column  752  (column  3 ) that is second from the rightmost column, and the middle symbol of column  3  has been changed to a WILD symbol  742 . 
     With the change to the third set of symbols, the array now includes three winning combinations: a four-owl-symbol combination (owl-WILD-WILD-WILD), a five-tree-symbol combination (tree-WILD-WILD-WILD-WILD), and a four-shield-symbols (shield-WILD-WILD-WILD). The wagering game pays the paytable awards for all three combinations, for a total award of 50+25+100=175 credits and displays the award in the win and credit meters  754 . 
     The abovedescribed sequence of selecting a set of symbols, changing the set to higher-value symbols, and displaying and evaluating the array with the higher-value symbols, may be repeated until a winning symbol combination is achieved or until one or more of various conditions are satisfied, and still remain true to the nature of the invention. 
     By utilizing different criteria for selecting the first and second sets, various game-play aspects may be modified so as to broaden the appeal of the invention with more players. As a non-limiting example of the different types of criteria, the wagering game may select a first set of symbols according to first criteria that includes selecting the lowest-value symbol(s) displayed in the array. 
     The array shown in  FIG. 4  includes two dagger symbols  442 , which are designated by the paytable of the wagering game to be the lowest-value symbols, and so the two dagger symbols  442  may be selected as an alternative first set of symbols. 
     As illustrated in  FIG. 8 , the wagering game has selected the two dagger symbols and changed them into shield symbols  842 , which is the next higher-value symbol of the paytable. The array is evaluated for winning combinations resulting from the two new shield symbols  842 , of which there are none. The wagering game then selects a second set of symbols according to second criteria that includes selecting all of the lowest-value symbols displayed in the array, and changes the symbols in the second set into the next-higher-value symbol. 
     In  FIG. 9 , the wagering game has selected all the displayed shield symbols (including the newly changed first set symbols) and changed them into witch-hat symbols  942 , which is the next-higher-value symbol. The array now includes two winning symbol combinations—a three-hat combination (witch hat-WILD-witch hat) and another three-hat combination (witch hat-witch hat-witch hat). The wagering game pays the paytable awards for both combinations for a total award of 5+5=10 credits and displays the award in the win and credits meters  454 . 
     Referring now to  FIG. 10 , there is shown a basic-game screen  1050  of another embodiment of the invention. Basic-game screen  1050  includes a plurality of symbol-bearing reels  1052 , game session credit meters  1054 , and touch screen buttons  1056 . The symbol bearing reels  1052  present an array of game symbols, such as the symbols  1042 , that represent the game outcome determined by the game logic based on a randomly generated number. 
     In this embodiment of the invention, the game outcome includes an ascending-feature outcome that includes a full column of WILD symbols  1044  (column  4 ), as determined by game logic. In this embodiment, when a full column of WILD symbols is displayed in the array, the wagering game evaluates the array for any winning symbol combinations and pays any associated awards to the player, and then changes the column to the left of the full column of WILD symbols into a full column of WILD symbols. For the next subsequent spin, after receiving another input from the player indicating a wager, the wagering game spins the video reels to display at least a portion of a new game outcome on the display, including the new column of WILD symbols. 
     As illustrated by  FIG. 11 , the new array includes the full column of WILD symbols  1144  in column  3 . The process of changing a left-adjacent column to a full column of WILD symbols may continue with each new spin until the column of WILD symbols reaches the leftmost column of the array, at which point it exits out of the array. 
     The invention may include various other and basic game features to provide variety and enhance player interest in the wagering game. Referring now to  FIG. 12 , there is shown a bonus game screen  1250  that may be part of a free-spin bonus. Of course, this embodiment may be implemented as a base game feature also. Bonus game screen  1250  includes a plurality of symbol-bearing reels  1252 , game session credit meters  1254 , and touch screen buttons  1256 . The symbol-bearing reels  1252  present an array of game symbols, such as the symbols  1242 , that represent the game outcome determined by game logic and based on a randomly generated number. 
     The symbol-bearing reels  1252  include a full column of WILD symbols  1244  in column  2 . For the next subsequent spin (seen in  FIG. 13 ), the WILD symbols  1344  in column  2  drop down one row while the remaining symbols of the array spin to randomly select the subsequent outcome. This sequence repeats with each subsequent spin until all the WILD symbols from the full column have dropped off the symbol array or, in some embodiments, until the free-spin bonus ends. 
     In some embodiments, the occurrence of another full column of WILD symbols during the free spin bonus triggers the drop-down sequence of the new full column, and in this way a player may experience a series of bonus awards as multiple columns of WILD symbols drop down incrementally in the symbol array. 
     Other bonus and game features may include designating a special symbol that, if it lands at the bottom, leftmost position of the array of symbols, changes to a WILD symbol that grows to encompass the bottom two positions at the left of the array. If a subsequent special symbol lands on top of the grown WILD symbols, the WILD symbols grow up to encompass another position. In at least one embodiment of a bonus feature, the WILD symbols that are grown from the special symbols will remain in the array until the bonus feature ends, for example, until a designated number of free spins are completed. 
     An embodiment of a game feature may designate specific reel symbols for “infecting” by WILD symbols. As a non-limiting example, a computer-themed game may include reel symbols such as Computer and Laptop symbols. When a WILD symbol occurs adjacent to either a Computer or Laptop symbol in the array, the WILD symbol infects the adjacent Computer or Laptop symbol (like a virus) and changes them into WILD symbols. Additionally, the new WILD symbols may infect adjacent Computer and Laptop symbols, and such infecting may continue until all adjacent Computer and Laptop symbols have been changed into WILD symbols. Of course, such an embodiment may be utilized in games having themes other than computer themes. 
     Also, a feature may include clumps of the same symbol displayed on a reel. For example, one embodiment features clumps of the same symbol appearing on the leftmost reel of the array during a bonus game. When the leftmost reel displays all matching symbols, any occurrence of the matching symbol that is displayed on other reels throughout the array may be changed into a WILD symbol. If the leftmost reel displays clumps of two different symbols, any occurrence of both symbols will change to a WILD symbol. 
     In another embodiment employing clumped symbols on a reel, a designated STACKED WILD symbol may occur in the array. If the STACKED WILD symbol fills an entire column, it is locked in place and triggers a bonus free spin feature. After each bonus spin, each position of the STACKED WILD column throws an additional WILD symbol into an adjacent reel, creating new WILDS on the reels to either side of the STACKED WILD column. 
     In yet another embodiment, if a full column of any symbol appears on the leftmost reel (i.e., reel  1 ) of the array, a feature may be triggered in which the full column is locked in place while the other reels begin to spin. Reel  2  stops spinning, and if any symbols on reel  2  match the symbols on reel  1 , then reel  2  locks in place also. If no symbols on reel  2  match reel  1 , then reel  2  spins again. Once reel  2  has stopped and locked in place, reel  3  stops spinning, and if any symbols on reel  3  match reel  1 , reel  3  locks in place. The process may continue until each reel in the array has a symbol that matches reel  1 . Alternatively, a WILD symbol may also be considered a match to the symbols displayed on reel  1 . Once all reels in the array include at least one matching symbol, any award for winning symbol combinations displayed in the array may be awarded to a player. 
     A WILD symbol may salvage a “just missed” opportunity. In one embodiment, a WILD symbol on a reel may land just off the symbol array, for example, just below the bottom row. Game logic may cause the missed WILD symbol to be pulled back up to the bottom row of the array, to be evaluated with the other symbols. Additionally, a recovered WILD symbol may grow into two WILD symbols for a subsequent spin, so that, the next time it just misses the symbol array, it may be pulled back up to occupy the two bottom reel positions. A recovered WILD symbol may grow repeatedly until it occupies the entire reel in the displayed array, and then reset to a single WILD symbol. 
     Game themes can be utilized to complement various game features. In one embodiment, a feature is triggered when a designated trigger symbol is displayed in between two other symbols on a reel. The particular embodiment has a dinosaur theme, although the feature can be adapted to operate with various other themes and generic games. The trigger symbol is an egg and, when the egg is displayed between two dinosaurs, it “hatches” to provide an award. The award may be free spins, may turn the egg symbol (or all displayed egg symbols, or various other symbols) into a WILD symbol(s) or a full column of wild symbols, and some or all WILD symbols may persist through multiple subsequent spins. The award may be related to a characteristic of a parent dinosaur. For example, there may be three different-colored dinosaurs on the reels, and the award may vary in response to the colors of the parent dinosaurs. 
     In one case in which the award is responsive to the specific colors of the parents, the hatching egg triggers a free spin bonus in which the player may select from a number of eggs. Whichever color of dinosaur that hatches from the selected egg may replace all the other-colored dinosaurs on the reels for the duration of the free spins, providing the potential for more bonus awards and more valuable egg hatchings during the free spin bonus. 
     In another embodiment, WILD symbols may migrate around the symbol array during successive spins. For example, when a WILD symbol appears in the symbol array and is not part of a winning symbol combination, the WILD symbol may shift one position to the left and appear in that position for the next spin. Additionally, the migrating WILD may continue to shift leftward each time it is not part of a winning symbol combination until it reaches the leftmost position in the array. Still further, the migrating WILD may stay in the leftmost position through successive spins until the WILD is part of a winning symbol combination. 
     The invention may further include an embodiment in which symbols in a winning combination are removed from the array and the next symbol above each the removed symbol “drops” into the empty position on each reel. After the symbols drop, the array is reevaluated for winning symbol combinations, which may also be removed and replaced by dropped symbols. The reevaluations may continue as long as a new winning symbol combination is generated by dropped symbols. 
     In another embodiment, WILD symbols can be randomly hidden behind symbols on the reels. When a symbol is removed (due to a winning symbol combination), the WILD symbol is revealed and replaces the removed symbol in the next symbol drop. Additionally, if the next symbol drop produces a winning symbol combination, the WILD symbol may stay in position for yet another (or multiple) symbol drop(s). Still further, WILD symbols that repeat for subsequent drops may increment a multiplier for each winning symbol combination after the first drop. In one embodiment, the WILD symbols can increment up to 5× multipliers before the WILD is removed from the array. Multiple WILD symbols can be revealed and held in position during a single cycle of removals and drops. Also, if a designated number of WILDS are revealed during a cycle, all the WILD symbols can automatically jump to 5× and then decrement by 1× for each subsequent drop until they are used up and removed. 
       FIG. 14 , described by way of example above, represents one algorithm that corresponds to at least some instructions executed by the CPU  30  in  FIG. 2  to perform the above described functions associated with the disclosed concepts. As seen in  FIG. 14 , a wagering is received  1410  to initiate a wagering game. The wagering game randomly selects  1420  a game outcome from a plurality of game outcomes and displays  1430  the selected game outcome to a player. The selected game outcome is evaluated  1440  for a winning outcome. In response to the game outcome including a winning outcome, the wagering game awards  1450  the player for the winning outcome. In response to the game outcome not including a winning outcome, a first set of game symbols is selected  1460  according to first criteria  1465  and changed  1460  into symbols having a higher value. The game outcome including the higher-value symbols is evaluated  1470  for a winning outcome. In response to the game outcome including a winning outcome, the player is awarded  1450  for the winning outcome. In response to the game outcome not including a winning outcome, a second set of symbols is selected  1480  according to second criteria  1485  and changed  1480  into still-higher symbols. 
     Each of these embodiments and obvious variations thereof is contemplated as falling within the spirit and scope of the claimed invention, which is set forth in the following claims. Moreover, the present concepts expressly include any and all combinations and subcombinations of the preceding elements and aspects.