Wagering game having reels with dynamic growing-symbol feature

A method of operating a gaming machine primarily dedicated to playing at least one casino wagering game, the gaming machine including an electronic display device, one or more electronic input devices, and a controller, the method comprising:

• detecting, via at least one of the one or more electronic input devices, a physical item associated with a monetary value that establishes a credit balance;
• initiating, via the controller, the casino wagering game in response to an input indicative of a wager covered by the credit balance;
• displaying, via the electronic display device, a plurality of symbol-bearing reels and an array of symbol positions, at least one reel of the plurality of symbol-bearing reels including a plurality of adjacent symbol locations and a variable symbol group, each symbol location of the plurality of adjacent symbol locations being associated with a certain symbol and being connected to an adjacent symbol location along at least one of a respective top or bottom edge, the variable symbol group occupying a first set of adjacent symbol locations of the plurality of adjacent symbol locations and includes an identical clumping symbol in each symbol location of the variable symbol group;
• spinning and stopping the plurality of symbol-bearing reels to land symbols on the reels in the symbol positions of the array, wherein as the at least one reel spins, the variable symbol group moves from the first set to a randomly selected second, different set of adjacent symbol locations of the plurality of adjacent symbol locations;
• and
• receiving, via at least one of the one or more electronic input devices, a cashout input that initiates a payout from the credit balance.

A gaming system, comprising:

• a gaming machine primarily dedicated to playing at least one casino wagering game, the gaming machine including an electronic display device and one or more electronic input devices;
• and
• a controller configured to perform the operations of:
• detect, via at least one of the one or more electronic input devices, a physical item associated with a monetary value that establishes a credit balance;
• initiate the casino wagering game in response to an input indicative of a wager covered by the credit balance;
• display, via the electronic display device, a plurality of symbol-bearing reels and an array of symbol positions, at least one reel of the plurality of symbol-bearing reels including a plurality of adjacent symbol locations and a variable symbol group, each symbol location of the plurality of adjacent symbol locations being associated with a certain symbol and being connected to an adjacent symbol location along at least one of a respective top or bottom edge, the variable symbol group occupying a first set of adjacent symbol locations of the plurality of adjacent symbol locations and including an identical clumping symbol in each symbol location of the variable symbol group;
• spin and stop the plurality of symbol-bearing reels to land symbols on the reels in the symbol positions of the array, wherein as the at least one reel spins, the variable symbol group moves from the first set to a randomly selected second, different set of adjacent symbol locations of the plurality of adjacent symbol locations;
• and
• receive, via at least one of the one or more electronic input devices, a cashout input that initiates a payout from the credit balance.