Regions as scales
The board is a grid, from 4×4 up to 7×7. Coloured rectangles are scales, each with a weight target. Tap two cells to swap their weights. A scale is balanced when the weights inside it add up to its goal; the level ends when every scale does.
Feel the balance
Rive animations under the board show whether each region is under, balanced or over its target, so the feedback is visual before you finish counting.
Logic in domain
Generation and validation live in a pure domain package: levels, overlapping regions, and the rules that keep a puzzle solvable. Presentation owns the board, BLoC and Rive; data stays ready for persistence later.