crossover

早期freebsd实现

update = 5;
newplane = 5;
width = 29;
height = 21;

exit:		(  0  0 c ) (  8  0 c ) ( 20  0 z ) ( 28  0 z )
		( 28 20 q ) ( 20 20 q ) (  8 20 e ) (  0 20 e );

beacon:		( 14  6 ) ( 18 10 ) ( 14 14 ) ( 10 10 );

line:		[ (  0  0 ) ( 20 20 ) ]
		[ (  8  0 ) ( 28 20 ) ]
		[ ( 20  0 ) (  0 20 ) ]
		[ ( 28  0 ) (  8 20 ) ];