Zentangle® is non-representantion and abstract. You are not trying to draw a person, a thing, or scene (you never get caught in the self-critical loop of "That doesn't look like a dog, or a tree or a face"). There is not up or down and not pre-planning, it's just about enjoying the process.
Your basic tools are paper, pencil and pen.
The method is based in five elemental strokes: • — C S O
3.5"x3.5" each one
(Ink and graphite on paper)