function s = UWhyperS(x,y,theta,R)
%HYPERS s(x,y,theta)
% for a given point (x,y) in the unit disk and \theta\in\S^1, returns the
% unique geodesic of second coordinate \theta that passes through (x,y)
% can handle several thetas

if x*x+y*y > 1,
    error(['(x,y) = (',num2str(x),',',num2str(y),') is outside the unit disk.']);
end

%%% FILL OUT 

end
        