http://croshet.blogspot.com/2011/12/blog-post_8194.html
http://video.sina.com.cn/v/b/29001666-1641219147.html
"+": 1 - += (, ) 2 - : ... 8 - : 3 "" 9 - : + 10 - + 11 - . 12 - 2 "+"
