Op-Art in Zentangle - string 205 and 206

Op art was a big thing in the sixties. I remember it since I was a teenager then and this movement in art affected not only the artscene but a lots of other things like clothes and stuff. When it comes to zentangle there are patterns that could belong to that movement. I did try Gord (Sue Zanker) a while ago and now I ran into a pattern I have done before: On Target (Barbara Finwall). I first found it on Pinterest in the beginning of my Zentangle journey and made some tries in my sketchbook. Here is my first try this time:

I used it with string 205 (which happened to be a string by Barbara Finwall!). This first round didn´t make me too happy. The pattern went to small, it was really hard to draw it! So I decided to give it one more round today with string 206 (Beth Snoderly):

This time I was wiser.  I also belive it shows more of the op-effect when the pattern is a little bigger. Aura Leah (Carla du Preez) was begging to follow this string and Crescent Moon also joined.

I am fascinated by these patterns that balances black and white in this way and what they may do with the feeling of depth and also how they creates meta-patterns. I also find them most relaxing to draw when I have learned them.