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.)