I tried a couple of different things. The 3d pen I have is not real precise so I more or less blobbed the filament in and sanded. The result is good but is a lot of work. I opted to use paint bottles with a nozzle lid. It was still impossible to do neatly and required sanding as well. It is much faster though. I plan on making a set with the 3d pen but just don't have the time right now. I am posting examples in "made". Looking forward to the additional tiles if you are still planning on creating them. Either way, this first set will be a Christmas gift for a family member.