There is nothing worse than a dull crayon. Even worse, you can't stick them in regular sharpeners because they jam! Luckily, you can now make your own crayon-specific sharpener. I got the basic idea from a model I saw online, and then made it workable. Printing is pretty easy, my 3mf file works just fine. You may want to sand down the edge after printing to increase the sharpening ability, but I didn't do that and it worked just fine.