code: def get_fake_data(*a):
      
      # add columns of data to the databox
      d['x'] = _n.linspace(0,10,100)
      d['y'] = _n.cos(d['x']) + 0.1*_n.random.rand(100)
      
      # update the curve    
      c.setData(d['x'], d['y'])
docs: Called whenever someone presses the "fire" button.