http://croshet.blogspot.com/2011/12/blog-post_8194.html
http://video.sina.com.cn/v/b/29001666-1641219147.html
"+": 1 - += (, ) 2 - : ... 10 - : 3 "" 11 - : + 12 - + 13 - . 14 - 2 "+"... 23 - : + = 24 - 25 - . +
