Picture is confusing. I'm not really sure what I'm looking at. Any other pictures from different angles?
Functional 3D Printing
Welcome fellow prototypers! This communities' purpose is to help others and share functional 3D Printing related information. While other 3D Printing Communities are a good resource, sometimes too many help posts get buried under memes and fluff. This will remain technically focused and keep the fluff removed. Please help your fellow 3D Printer hobbyists as much as you can with their issues! and showcase your functional prints and how you use or created them.
It's a hollow post you are looking at from the top down, the rails poke in from the sides and the print holds them do they won't move back out again
Oh ok, So the part prevents the fence portions from being pulled out.
Yep, exactly. Here's a photo from the fence perspective https://i.imgur.com/MmZAoeW.jpg
Commercially this type part is available but pretty expensive.