0 O O O O @ @ @ @ @ | 0 O O O O O O O O O | 0 @ @ @ @ @ @ @ @ @ | 0 O O O O O O O O @
1 O O O O @ @ @ @ @ | 1 O O O O O O O O O | 1 O @ @ @ @ @ @ @ @ | 1 O O O O O O O @ @
2 O O O O @ @ @ @ @ | 2 O O O O O O O O O | 2 O O @ @ @ @ @ @ @ | 2 O O O O O O @ @ @
3 O O O O @ @ @ @ @ | 3 O O O O O O O O O | 3 O O O @ @ @ @ @ @ | 3 O O O O O @ @ @ @
4 O O O O @ @ @ @ @ | 4 @ @ @ @ @ @ @ @ @ | 4 O O O O @ @ @ @ @ | 4 O O O O @ @ @ @ @
5 O O O O @ @ @ @ @ | 5 @ @ @ @ @ @ @ @ @ | 5 O O O O O @ @ @ @ | 5 O O O @ @ @ @ @ @
6 O O O O @ @ @ @ @ | 6 @ @ @ @ @ @ @ @ @ | 6 O O O O O O @ @ @ | 6 O O @ @ @ @ @ @ @
7 O O O O @ @ @ @ @ | 7 @ @ @ @ @ @ @ @ @ | 7 O O O O O O O @ @ | 7 O @ @ @ @ @ @ @ @
8 O O O O @ @ @ @ @ | 8 @ @ @ @ @ @ @ @ @ | 8 O O O O O O O O @ | 8 @ @ @ @ @ @ @ @ @

やっぱりわからないかもしれない。
例えば線対称なら上図のようになりますよね(@が着手候補)
回転対称ってどう半分になりますか？