var x:Number = startPos % width;
            var y:Number = int( startPos / width );

            var tl:Boolean = ( x > 0 && y > 0 ) ? ( gridVector[ startPos - 1 - gridWidth ] == 1 ) : true;
            var t:Boolean = ( y > 0 ) ? ( gridVector[ startPos - gridWidth ] == 1 ) : true;
            var tr:Boolean = ( x < gridWidth-1 && y > 0 ) ? ( gridVector[ startPos - gridWidth ] == 1 ) : true;
            var l:Boolean = ( x > 0 ) ? ( gridVector[ startPos - 1 ] == 1 ) : true;
            var r:Boolean = ( x < gridWidth-1 ) ? ( gridVector[ startPos + 1 ] == 1 ) : true;
            var bl:Boolean = ( x > 0 && y < gridHeight-1 ) ? ( gridVector[ startPos - 1 + gridWidth ] == 1 ) : true;
            var b:Boolean = ( y < gridHeight-1 ) ? ( gridVector[ startPos + gridWidth ] == 1 ) : true;
            var br:Boolean = ( x < gridWidth-1 && y < gridHeight-1 ) ? ( gridVector[ startPos + 1 + gridWidth ] == 1 ) : true;
            return ( tl ? 1 : 0 ) + ( t ? 1 : 0 ) + ( tr ? 1 : 0 ) + ( l ? 1 : 0 ) + ( r ? 1 : 0 ) + ( bl ? 1 : 0 ) + ( b ? 1 : 0 ) + ( br ? 1 : 0 );