Sugar Rush demo: clusters on a seven-by-seven grid
Sugar Rush replaces reels with a square field. Symbols fill a seven-by-seven grid and the engine looks for clusters — groups of five or more of the same symbol touching each other horizontally or vertically. Diagonals do not count. When a cluster forms it pays and vanishes, symbols above fall into the gap, fresh ones drop from the top, and the search runs again. The tumbling continues until a drop yields no cluster.
That adjacency rule is a bigger deal than it sounds. In a scatter-pay game the engine only has to count symbols; here it has to find connected components. Two grids with an identical number of the same symbol can pay very differently depending on whether those symbols happen to touch. That adds a geometric layer on top of the probabilistic one, and it is why cluster games feel structurally different to play even when the underlying draw is the same kind of random.
The Sugar Rush free play version here runs the identical logic on virtual credits, which makes it a good place to actually watch clusters form rather than just wait for the number at the bottom of the screen to change.