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.)