st=>start: Start|past:>http://www.baidu.com
e=>end:  Ende|future:>http://www.baidu.com
op1=>operation:  My Operation
op2=>operation:  Stuff|current
sub1=>subroutine:  My Subroutine|invalid
cond=>condition:  Yes or No|approved:>http://www.google.com
c2=>condition:  Good idea|rejected
io=>inputoutput:  catch something...|future
st->op1(right)->cond
cond(yes, right)->c2
cond(no)->sub1(left)->op1
c2(yes)->io->e
c2(no)->op2->e