gull call.                            
  
                                          
 the seagull is  a  metaphysics trick;  a 
 world-builder's  shortcut, to  define  a 
 section  of reality and  imply its size: 
 place  a flock of  birds at the edge and 
 make  their  calls  tesselate  over  the 
 entire volume                            
                                          
 a seagull  can  be defined by as  little 
 as  five  vertices;  six  triangles.  (i 
 would  recommend handling  in swarms  of 
 at least a dozen birds.)