After several years, the white caps for my railing on my porch had discoloured badly and I wanted to freshen it up. I designed this model to duplicate the look of the original. It prints well 2x2 on a P1S, I am using PLA although another material would probably be better since its outdoors and in sun.

My railing is 3 inch x 3 inch, this fits perfectly but you have to push one corner in and then squeeze slightly to put the other corner in. This tight fit means it shouldn't move once properly installed.