After making lots of the basic vortex coils, I then tried to make squared ones. I didn't actually got it figured out right away. I knew how to make simple square quilling shapes but I didn't know how to get that vortex pattern inside the square. Then I figured that everything had to start with the basic vortex coil shape. Once I came to that realization, then it became very clear what I should do in order to get that square vortex coil pattern.
As promised, I have made a video tutorial on how to make the square vortex coils. So many people have requested for me to make it. It is not easy to explain with mere words on how to do it, so making a video is the best way for me to get the idea across.
The multicolour square vortex coil pattern I made in the video was made using 4 different colours of blue shredded quilling papers. My shredded quilling papers are 3mm wide and 297mm long. I used 80gsm A4 paper to make these shredded papers. You can use any type of quilling paper you fancy but I think that if you plan to make a big size vortex coil, then I suggest you use a much thinner paper, and 80gsm would be great. If you plan to use only one strip, then you can use thicker type of quilling papers.
Do check out the video tutorial below and have fun quilling! :)