[outdoor/indoor theory]
It's a really great thing, that there are places to spray)paint outside, because the aerosol really does a number on my judgement when conceptualizing indoor murals.

[notebook to wall transition theory]

Do you have notebooks full of interesting drawings that would be awesome to see manifested onto full-scale walls? Here is one way of making the analogies between your pens, and the spraypaint cans you use.

1. Fine-line pens could potentially be very fat markers.

It's sometimes okay to use markers in spraypaint mural situations. There are some uses, that will be found often in the pen collection of lines that are considered "005" by Sakura Micron Standards.

2. Does the order of the lines still hold true?

On pen and paper, it's often that the lines are drawn in a specific chronology. On mural, however, these lines might hold a slightly different order. Spraypainting murals often require the repeated over-painting of certain lines, and due to the inaccuracy of the medium, it's more strictly adherent to the formula, background first, foreground last.

recent theories.
i thought of a really great theme for an outdoor skatepark, which is to paint all the ramps jet black, then paint lines on them that look like a highway or street, including the double yellow for the major routes, white dotted for lane changing, arrows directing towards certain ramps, and other such visual cues that have neverbefore seen the likes of a skateboard park. a cool idea.