A border/per​imeter/rec​tangle around the inset plot, in a subplot environment

In the following subplot environment, how can I draw a red border/perimeter/rectangle around/wrapping the inset plot?

fig = figure;
for i = 1 : 6
    subplot(3,2,i)
    scatter(rand(1,10),rand(1,10))
end
axes(fig,'Position',[.1 .2 .2 .2])
plot(1:5,rand(1,5))

Answer 1

[Voss]

Here are a couple of options:

fig = figure;
for i = 1 : 6
    subplot(3,2,i)
    scatter(rand(1,10),rand(1,10))
end
ax = axes(fig, ...
    'Position',[0.02 0.12 0.29 0.29], ...
    'Visible','off', ...
    'ClippingStyle','rectangle', ...
    'XLim',[-0.01 1.01], ...
    'YLim',[-0.01 1.01], ...
    'XTick',[], ...
    'YTick',[]);
line(ax, ...
    'XData',[0 0 1 1 0], ...
    'YData',[0 1 1 0 0], ...
    'Color','r', ...
    'LineWidth',3, ...
    'LineJoin','miter', ...
    'Clipping','off')
axes(fig,'Position',[0.1 0.2 0.2 0.2])
plot(1:5,rand(1,5))
xlabel('xlabel')
ylabel('ylabel')

fig = figure;
for i = 1 : 6
    subplot(3,2,i)
    scatter(rand(1,10),rand(1,10))
end
axes(fig,'Position',[0.02 0.12 0.29 0.29], ...
    'Box','on', ...
    'XTick',[], ...
    'YTick',[], ...
    'XColor','r', ...
    'YColor','r', ...
    'LineWidth',3)
axes(fig,'Position',[0.1 0.2 0.2 0.2])
plot(1:5,rand(1,5))
xlabel('xlabel')
ylabel('ylabel')

[Sim]

Cool! Thanks a lot @Voss! :-)

Answer 2

[Sim]

Got it, with the Control Axes Layout options!

fig = figure;
for i = 1 : 6
    subplot(3,2,i)
    scatter(rand(1,10),rand(1,10))
end

ax = axes(fig,'Position',[.1 .2 .2 .2]);
plot(1:5,rand(1,5))
xlabel('my xlabel')
ylabel('my ylabel')
annotation("rectangle",ax.OuterPosition,Color="red",LineWidth=2)