neighbors method
Implementation
Neighbors neighbors(int x, int y) {
final val = get(x, y);
return Neighbors(
topLeft: x > 0 && y > 0 && get(x-1, y-1) == val,
top: y > 0 && get(x, y-1) == val,
topRight: y > 0 && x < width-1 && get(x+1, y-1) == val,
left: x > 0 && get(x-1, y) == val,
right: x < width - 1 && get(x+1, y) == val,
bottomLeft: x > 0 && y < height-1 && get(x-1, y+1) == val,
bottom: y < height -1 && get(x, y+1) == val,
bottomRight: x < width - 1 && y < height -1 && get(x+1, y+1) == val
);
}