Sn b

Sn bSn bSn bSn bSn bSn b
Sn bSn bSn bSn bSn bSn b
Sn bSn bSn bSn bSn bSn bSn bSn bSn bSn bSn bSn bSn bSn bSn bSn bSn bSn bSn bSn bSn bSn bSn bSn bSn b