:- use_module(contestlib, [writeN/2, write_int/2]).

cross(N) :-
	FirstIndent = 5,
	MiddleIndent is 2*N - (N mod 2) - 3,
	UpperLeft = 1,
	cross(N,FirstIndent,UpperLeft,MiddleIndent).

cross(0,_,_,_) :- !.
cross(1,FirstIndent,UpperLeft,_) :- !,
	writeN(FirstIndent,' '),
	write_int(UpperLeft,2),
	nl.
cross(N,FirstIndent,UpperLeft,MiddleIndent) :-
	UpperRight is UpperLeft + 1,
	write1line(FirstIndent,UpperLeft,MiddleIndent,UpperRight),
	N1 is N - 2,
	FirstIndent1 is FirstIndent + 2,
	UpperLeft1 is UpperLeft + 4,
	MiddleIndent1 is MiddleIndent - 4,
	cross(N1,FirstIndent1,UpperLeft1,MiddleIndent1),
	DownLeft is UpperLeft + 3,
	DownRight is UpperLeft + 2,
	write1line(FirstIndent,DownLeft,MiddleIndent,DownRight).

write1line(Spaces1,I1,Spaces2,I2) :-
	writeN(Spaces1,' '),
	write_int(I1,2),
	writeN(Spaces2,' '),
	write_int(I2,2),
	nl.