How to run two graphs simultaneously

Hi all,
I want to run two graph simultaneously. Codes are like following:
fg=gr.topblock()
fg.connect(//some blocks)
fg.connect(//some blocks)
fg .start()
It didn’t work and now I know there can be only one topblock running.
But is
there any way else to run two parallel graphs? Can anyone show me some
example codes?
Best Regards,

Ying Dai

On Sat, 10 Oct 2009, Ying Dai wrote:

I want to run two graph simultaneously. …

Like this? Here are some screen shots:

http://staff.washington.edu/jon/gr-osx/gr-signoise.html

Can anyone show me some example codes?

The code is linked to the page above.

Jon Jacky