[nailer]

> They've got the unique property of not making you think about details

Paper and pen is good too, but it makes me think about details like:

* Whether a line is straight

* Whether my writing is legible

* Whether my writing fits in the container

etc. I don't have to think about these when using a drawing app. Also I can send my render to an XML slicing service. On the other hand, connections are much easier to draw on paper.