Zentangle is an abstract drawing technique, using black ink on white paper, which is quite easy and can be done by everyone.
Zentangle is an 'art therapy' where one can meditate and calm by drawing. We only need to concentrate and then describe any pattern that is repeated, repeatedly.
In drawing zentangle, usually an artist does not have a final "goal", does not expect to be drawn to a certain form, and vice versa, they only draw after "instinct" alone.
Easy tutorial, let your hand draw whatever line you want, no need to think about what will happen.
Zentangle is different from graffiti. Where streaks are 'graffiti' in all directions (generally radial), zentangle is in the form of a pattern drawn repeatedly.
may be useful