How can I customize the positions of legend elements?

To make a two-column legend, the general consensus seems to be that you need to create two separate legends and manually place them side by side. Solution simplified from discussion here.

x = 1:10;
y1 = rand(1, 10);
y2 = rand(1, 10);

h1 = plot(x, y1, '-');
hold on
h2 = plot(x, y2, '-.r');

ah1 = gca;
ah2 = axes('position',get(gca,'position'), 'visible','off');

legend(ah1, h1, 'Location', [0.5 0.85 0.15 0.05], 'y1')
legend(ah2, h2, 'Location', [0.7 0.85 0.15 0.05], 'y2')

Of course this is possible. See an explanation here: http://undocumentedmatlab.com/blog/multi-column-grid-legend/