Utilizing Excel's turing capabilities to create Conway's 'Game of Life'

One way to sharpen the sword is to devise a solution for an invented problem.

This is some fooling around with "Flood Fill":

FloodFillλ = 
LAMBDA(grid, current_colors, new_colors,
    LET(
        h, ROWS(grid),
        w, COLUMNS(grid),
        x, {-1; -1; -1; 0; 1; 1; 1; 0},
        y, {-1; 0; 1; 1; 1; 0; -1; -1},
        new_colors, XLOOKUP(grid, current_colors, new_colors, ""),
        change_colors,LAMBDA(i, j,
                    LET(
                        active, INDEX(grid, i, j),
                        connected, OR(active = INDEX(grid, i + x, j + y)),
                        new, INDEX(new_colors, i, j),
                        swap, (connected) * (OR(active = current_colors)),
                        fill, IF(
                            active = "",
                            "",
                            IF(swap, new, active)
                        ),
                        fill
                    )
                ),
        return, MAKEARRAY(h,w,change_colors),
        return
        )
    );