Model originally uploaded to Thingiverse at https://www.thingiverse.com/thing:1684548.
This is just your basic string / floss sorter for needle point or cross stitch. Like all things it is better when you can complicate it and add 3D Printing.
This is a customizable track with holes in it to sort the string / floss. As you adjust the length and width it will attempt to best fit as many holes as it can.