Script help - npc chooses random wall and spray paints a decal on that wall.

[SandMouseAnarchy]

Hi all, I'm looking into the possibility of having an npc spray paint a decal on a wall. Like a gang tag or a "down with McDunner" sign.

 

I think it would be best to have the npc pick out a wall around them at random, so that the decal could appear anywhere, not just on selective wall pieces.

 

Does anyone know how to do this?

 

I suppose that spawning in the decal is the easy part, relatively speaking.

But how does one go about making an npc choose a random wall to stand at?

Is there a 'detect nearest wall' or 'detect 90' surface' script for example?

 

Any ideas would be massively appreciated :)