Alternate posts between two columns using Masonry

I’m running the Twenty Twelve theme with this tutorial on creating a Masonry grid-like layout: https://premium.wpmudev.org/blog/add-masonry-grid-layouts-to-your-wordpress-site-with-just-css/

Is there any way to alternate posts between the two columns instead newest to older posts starting in the left column and continuing onto the right column?

This is what it looks like currently: https://104.131.43.86/

Thanks in advance!