function six( p, used, n )
	pieces = [
		1, 2, 3, 4, 5, 6;
		4, 5, 6, 1, 2, 3;
		3, 4, 5, 1, 2, 6;
		1, 2, 4, 5, 6, 3;
		4, 6, 1, 2, 5, 3;
		1, 5, 3, 4, 6, 2;
		5, 2, 6, 1, 3, 4;];

	% 找到一組解
	if ( n == 8 )
		p
		return;
	end

	for i = 1:7
		if( used(i) == 1 )
			continue;
		end

		r = pieces(i,:);
		used(i) = 1;

		for j = 1:6
			% 第一片不旋轉
			if ( n == 1 && j ~= 1 )
				continue;
			end

			r = clshift(r);
			p(n,:) = r;
			if( check(p) )
				six( p, used, n + 1);
			end
		end

		used(i) = 0;
	end
end