This is a VERY simple example of Openscad in use.
The problem was that we had a brass mailbox and we lost one of the plugs that is on each end of the hinge. Since I had a role of Brass PLA filament I quickly worked up this design and printed it out.
It is VERY fast to print. I printed it a couple of times just to get the right diameter.
Essential tool: everyone should get a Micrometer. They are less than $10 and essential when building things that have to fit with the real world.
I re-did this item using Fusion 360. I included the source file and the STL. Since this is such a simple design it is a good example for Fusion360 as well.