A little bit of colour and design theory to help you create interest.
I used three sizes in pens to create different thicknesses of line.
I used shading to create depth.
I used lines going in different directions to create movement.
Because of the above some features in the design stand out more than others.
All these things combined create a lot of interesting things to look at in a very small pattern.
My Pattern I used is:
Rolling In - a variation
The other pattern I used:
A spiral repeated in various sizes. I have seen this often and am not sure if someone has claimed it as their design. If so let me know and I am happy to give them credit.