similistar(Commands1,Commands2) :-
	collect_stars(Commands1,Stars1),
	collect_stars(Commands2,Stars2),
	canonical_stars(Stars1,Canonical1),
	canonical_stars(Stars2,Canonical2),
	Canonical1 == Canonical2.

canonical_stars([],[]).
canonical_stars(Stars,CanonicalStars) :-
	Stars = [star(StartCol,InitialLine)|RestStars],
	max_line(RestStars,InitialLine,StartLine),
	canonical_stars(Stars,StartCol,StartLine,CanonicalStars).

canonical_stars([],_,_,[]).
canonical_stars([star(X,Y)|R],StartCol,StartLine,[star(X1,Y1)|R1]) :-
	X1 is X - StartCol,
	Y1 is Y - StartLine,
	canonical_stars(R,StartCol,StartLine,R1).