[hchen19@beeblebrox prototype3]$ python txtinterface.py 
> 0 0 4
plot observer get a new data:  4.0
spreadsheet observer get new data:  4.0
> 5 5 9
plot observer get a new data:  9.0
spreadsheet observer get new data:  9.0
> q
[hchen19@beeblebrox prototype3]$