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.)