This lets you add springs
            to strokes with tubes to give the tubes reactive, interconnected
            motion. By animating the movement of the surface with the springed
            tubes on it, the tubes will react appropriately.
         
         Paint Effects > Brush
                  Animation > Make Brush Spring >   
  
            
            These are the options
               in the Make Brush Spring Options window.
            
            - Spring Stiffness
- 
                  Defines the rigidity of the brush spring.
                        If you increase the stiffness too much, the brush spring might stretch
                        and contract excessively.
                      
- Spring Damp
- 
                  Defines a damping value to mute the spring action.
                        A high value causes the spring length to change more slowly. A low
                        value causes the length to change quickly. 
                      
- Spring Travel
- 
                  Defines how far the stroke tubes can swing.
                      
- Start Frame
- 
                  Sets the frame in which the spring behavior begins.