11 beacon: ( 10 6 ) ( 23 6 )
12 ( 23 16 ) ( 15 16 ) ( 7 16 )
15 airport: ( 23 8 x ) ( 15 12 w ) ;
17 line: [ ( 10 1 ) ( 10 5 ) ]
22 [ ( 8 16 ) ( 14 16 ) ]
23 [ ( 16 16 ) ( 22 16 ) ]
25 [ ( 23 9 ) ( 23 15 ) ]
26 [ ( 15 7 ) ( 15 11 ) ]
27 [ ( 15 13 ) ( 15 15 ) ]
31 [ ( 24 17 ) ( 26 19 ) ] ;