clear all
clf
format short


yS=linspace(-20,20,11);
x=linspace(-50,50,101);

N=length(yS);



% for i=1:N
%     yA=yS(i);
%     plot(x,yA.*ones(length(x),1),'-b'),grid on, hold on
% end



xend=length(x);

for i=1:N
    yA=yS(i);
    line([x(1) x(xend)],[yA(i) yA(i)]), grid on, hold on
end

hold off