Style even and odd Tumblr posts
<p>I had an idea to do a Tumblr theme where the posts are displayed differently depending on if they're even or odd. I know how to do this just straight HTML, however, I'm new to Tumblr coding. This would be what I mean:</p>

<p><img src="https://i.stack.imgur.com/NXpQP.png" alt="Mockup of what I&#39;m looking to accomplish"></p>

<p>Any thoughts? Is this something that can be done within Tumblr's code? I know how to insert the <code>{Block: Post}</code> stuff, but I'm unsure how to make Tumblr split the posts as even or odd...</p>