There are so many things you can use Zentangle techniques in. Last week one of my good friends celebrated her birthday. She had a blank canvas covered checkbook that was waiting to be tangled. She wanted her initial on it. This didn't take me very long to do this for her. It was done in one evening.
The process was started with a post-it note. I sketched out a large letter 'R' on the post-it and cut it out. I placed it on the checkbook and using a Sakura IDentipen, tangled around it as I normally would. I used tangle patterns as my strings. Since this is a checkbook that will be handled often I didn't add pencil shading as I normally do but simply added a few extra lines here and there. I finished it off with the dashed line inside the 'R'.
Tangle patterns used; Zenith, W2, Copada, Printemps, Meer, Leezy, Bales, and Ditto.