Not really sure that is mid century, but is a new fad. Check out you tube for tutorials on that. They are very helpful.
Here's how one family built their mid century horizontal fence Liz!
Here's another link that shows you how to build a gate!
This tutorial should help: http://videos.homedepot.com/detail/videos/fencing/video/4728259920001/building-a-horizontal-fence?autoStart=true