createPath method
Implementation
@override
Path createPath(double size, Neighbors? neighbors) {
final big = Path()
..addRect(Rect.fromLTWH(0, 0, size, size));
final small = Path()
..addRect(Rect.fromLTWH(size / 7, size / 7, size * 5 / 7, size * 5 / 7));
return Path.combine(PathOperation.xor, big, small);
}