Gaming system and method with a persistent element feature

A method of operating a gaming machine, the method comprising the operations of:

• accepting, via a value input device, a physical item associated with a monetary value to establish a credit balance;
• conducting, by game-logic circuitry, a base game including:
• presenting, by a presentation assembly, a plurality of symbol-bearing base reels, a base array, and a plurality of N persistent elements, each persistent element having an associated game feature;
• spinning and stopping the plurality of base reels to land symbols from the base reels in the base array;
• and
• in response to the landed symbols including at least one accumulation symbol:
• animating an addition of the at least one accumulation symbol to a first one of the plurality of persistent elements and further animating transference of the at least one accumulation symbol from the first one of the plurality of persistent elements to M−1 additional ones of the plurality of persistent elements, where M represents a randomly determined cascade level from 1 to N;
• and
• randomly determining whether or not to award the game features associated with the 1−M persistent elements;
• and
• in response to awarding the associated game features, implementing, by the game-logic circuitry, the one or more game features in either the base game or a bonus game;
• and
• receiving, via at least one of one or more electronic input devices, a cash out input that initiates a payout from the credit balance via a value output device.