What isn't working when you use three plots instead of two?
I just tested your code, and the only thing I noticed is that as the plots get small, the length of the ticks gets really small. You could try increasing the tick length:
x = 0:1:16;
multiplier = [0.5 1.5 1];
n = 3;
for s = 1:n
hA = subplot(1,n,s);
plot(x, multiplier(s)*x)
axis([0 15 0 15])
pbaspect([1 1 1])
grid on
hA.YAxis.MinorTickValues = 0:1:15;
hA.XAxis.MinorTickValues = 0:1:15;
set(hA,'yMinorTick','on')
set(hA,'xMinorTick','on')
hA.TickLength = [0.05 0.05]; % Increasing the tick length
end
