The size here is really important because it will determine the angle of the coil. In this example I used 600x600. Look at the 2 examples at the end of the tutorial, the variation was created on 800x600, notice that the angle is a little wider and less round. Personally I think I prefer the 800x600, but experiment with different sizes and see how you like the results.
Create a new layer and choose filter>sketch>halftone pattern.
Size =2 (use higher for a higher res image)
Push the contrast pretty high
