UPDATE 6/12/19: I've fixed an error in the X-Tile that was an oopsie in tinkercad.
Solving a cube fast requires developing a lot of hand eye coordination. After you've mastered that, why not work on your hand touch coordination? These tiles can be glued to the sides of a cube to make it suitable for solving without looking at it. This is a great mental workout for those who have already mastered a normal cube and an opportunity for those who are visually impaired to take on the challenge of solving a cube.
These tiles will likely fit a variety of different cubes, including Rubik's brand, but were designed specifically to make sure they fit on the Moyu Weilong GTS2. All 6 tiles are symmetrical, so that you don't have to worry about orientation.
N/A I used PLA
I'd suggest Red, Blue, Green, White, Yellow, and Orange :)
To make it extra special you could print the different tiles in 6 different colors for that classic look.
You will need to print 6 of each tile.
You should probably remove any old stickers that are on the cube if it is a stickered cube.
Make sure to give the cube a good cleaning first and let it totally dry.
Orientation of the parts doesn't matter, but you should make sure that you glue parts on one whole side at a time. It would be annoying if you glued the parts on in such a way that it was unsolveable!
You will need a donor cube to convert. I'm converting my old speed cube.
You will need an adhesive of some kind. Super glue should work.