This 3D art is made with yarn, glue, foil and good old Sharpie markers. The simpler the design, the better, as proven by Lia here.
1. Draw a design with white glue on a heavy matte board.
2. Place thick yarn on the glue, press lightly and trim extra if necessary.
3. Rub the entire board heavily with a glue stick. Be sure to get right up to the edges of the yarn.
4. Place a sheet of aluminum foil over the board. Wrap the edges and rub down to make the yarn stand out.
5. Color as desired with Sharpie markers. The brush style allow for easy solid coloring, if you can afford them.