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.)