code: function( angle ){
  
              var r = this.radius
                  ;
  
              // circles are symetric... so angle has no effect
              if ( this._aabb.hw !== r ){
                  // recalculate
                  this._aabb = Physics.aabb( -r, -r, r, r );
              }
  
              return Physics.aabb.clone( this._aabb );
          }
docs: extended