The Reel That Upgrades the Next Reel A Bonus Game Where Jackpot Symbols Breed More Jackpot Symbols

This application covers an electronic bonus game in which symbols landing on an early reel change the contents of the reels still spinning beside it: a reel upgrade symbol on the first reel injects jackpot upgrade symbols into a later reel strip, and land enough jackpot symbols across the grid and a jackpot feature fires. The applicant is Aristocrat Technologies Australia, the Sydney based arm of gaming giant Aristocrat Leisure, and the filing is the fifth Australian generation of a family stretching back to 2017.

The Problem

The background section walks through how an electronic gaming machine works. A player establishes a credit balance, places a wager, and plays a base game, most commonly a slot game displayed as symbols in a row by column matrix, with winning combinations read along paylines and paid according to a pay table. Attaining a particular combination or trigger in the base game can qualify the player for a secondary game or bonus round, which offers additional game instances, credits, awards, jackpots or progressives.

Underneath all of it sits a random number generator that determines each outcome, with the game designed to return a set percentage of the amount wagered to the player over many plays. The specification notes that this return to player figure and the randomness of the RNG are fundamental to fairness and therefore highly regulated. The unstated commercial problem is the familiar one in this industry: within those regulatory constraints, machines compete on anticipation. A bonus round where the reels are fixed from the moment they start spinning offers only one moment of suspense. The design described here is built to stack several of them into a single spin.

What This Invention Does

The claimed machine has the standard hardware, a display, a player input interface and a credit input mechanism, plus a game controller running a very particular sequence. The controller spins a set of reel strips and stops them one at a time. When the first reel stops, the controller checks whether a reel upgrade symbol has landed. If it has, the controller reaches into at least one of the reels that is still spinning and replaces a replaceable symbol on that strip with a jackpot upgrade symbol. The next reel stops, and if a second reel upgrade symbol appears there, another replacement is made on a strip still in motion. Only then do the remaining reels stop.

In the exemplary embodiment the cascade runs left to right: an upgrade symbol on the first reel strip seeds jackpot upgrade symbols into the third, and an upgrade symbol on the third seeds them into the fifth. The upgrade symbols that did the seeding are themselves swapped out for jackpot upgrade symbols, so the trigger converts into the currency it creates. When everything has stopped, the controller counts the jackpot upgrade symbols showing across the display, and if the count exceeds a threshold, a jackpot feature is triggered.

The effect for the player is a bonus spin whose odds visibly improve while it is still in progress. Each early reel that lands well does not just pay, it physically enriches the reels yet to stop, and the machine can show that happening. The application claims the idea three ways, as a gaming machine, as a method, and as a computer readable storage medium carrying the instructions, which is standard practice for covering the machine, the operation of the machine, and the software that could be loaded onto someone else’s machine.

Key Features

• Reels edited mid-spin. Symbols on strips that are still spinning are replaced in response to what has already landed, so the composition of a reel can change during the spin it is part of.
• A left to right upgrade cascade. In the exemplary embodiment, an upgrade symbol on reel one adds jackpot symbols to reel three, and reel three’s upgrade symbols add jackpot symbols to reel five.
• Triggers that convert into prizes. The reel upgrade symbols that set off each replacement are themselves replaced with jackpot upgrade symbols, feeding the final count.
• A counted jackpot threshold. The jackpot feature fires only if the number of jackpot upgrade symbols displayed across the reels exceeds a threshold, keeping the mathematics tunable.
• Bonus game framing. The field section describes the feature as an electronic bonus game triggered from a primary or base game, layered on top of a conventional wagering game.
• Three parallel claim families. The same sequence is claimed as a machine, a method, and an article of manufacture holding the instructions, covering hardware, operation and software distribution.

Who Is Behind It

Aristocrat Technologies Australia Pty Limited is the local operating and patent holding company of Aristocrat Leisure Limited, the ASX listed gaming company founded in Sydney in 1953 and today one of the largest manufacturers of gaming machines and casino content in the world. Aristocrat’s machines and game franchises dominate venues across Australia and are fixtures on casino floors in the Americas, Europe and Asia, and the company files patent applications on game mechanics at a steady industrial rate.

The two named inventors, T. Grant Bolling and Michael P. Casey, are US based game designers, and the family’s origin reflects that. This application is a divisional of Australian application 2023266390, itself a divisional of 2021225256, itself a divisional of 2019275667, itself a divisional of 2018204238, which claims priority from United States provisional application 62/536,272, filed on 24 July 2017 under the same title. Four successive divisionals mean this 2017 mechanic has been kept continuously pending in Australia for nearly nine years.

Why It Matters

Gambling in Australia runs through roughly 200,000 electronic gaming machines, one of the highest densities in the world, and the games on them are refreshed constantly. In that market, a mechanic that layers extra anticipation onto a spin without touching the regulated return to player mathematics is commercially valuable, which is why symbol replacement, collection meters and upgrade features have become a defining arms race among the big manufacturers. This design’s contribution is the timing: the replacement happens while the reels are spinning, in response to reels that have already stopped, which turns a single random draw into a staged, watchable sequence.

The filing strategy says as much as the mechanic. A provisional filed in 2017 and shepherded through four Australian divisionals is a family being kept deliberately open, so claims can be reshaped as competitors’ features and Aristocrat’s own products evolve. Jackpot triggers built on counting special symbols sit close to progressive jackpot systems, one of the most valuable and most litigated corners of gaming intellectual property, and a pending application is a flexible instrument there in a way a granted one is not.

Related Concepts

• Slot machine – the reel based game format the bonus feature is built on.
• Progressive jackpot – the class of accumulating prize the specification lists among secondary game awards.
• Random number generation – the regulated source of randomness behind every outcome the game displays.
• Aristocrat Leisure – the Sydney founded parent company behind the applicant.
• Gambling in Australia – the market context in which Australian gaming machine patents are filed.
• Video game – the broader electronic game category reflected in the application’s A63F 13/00 classification.

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AU 2026202112 was published in the Australian Official Journal of Patents on 9 April 2026 and is open for public inspection. Patent applications represent inventions that are sought to be protected and do not necessarily reflect commercially available products.