I remember seeing such a link here but cannot find it back. I designed the letter C in 3D GameStudio in such a way that it became a link to form a bracelet or necklace chain. Beauty is that you can use all colours of the rainbow to make this jewelry. I remember from my youth how I loved those bracelets. My grandkids love them too :)

Simply choose the letter C and design it in such a way that it can be used as a link to another one to chain a bracelet or a necklace together. I did this in 3D GameStudio, exported it as a 3DS file and let Adobe CC student version make a STL file from it.