I knew of a businessman with a large production facility in a bad neighborhood. And for some reason, the building wall facing his parking lot was irresistible to graffiti vandals. He even got a ticket when after a weekend, the police cited him for not removing graffiti fast enough.
That did it. He was ticked off. So he had his shop foreman drill small holes at intervals in the wall, through which they inserted flush high pressure paint spray nozzles. A line of them about 4’ off the ground and 4’ apart, running most of the length of the wall. Inside the wall, they were connected to a pipe leading to a high pressure container of glow in the neon green paint.
Then he put up a couple of cameras for his security guards to watch the wall, along with a switch for the paint.
Sure enough, several taggers got painted with a heavy coat of bright neon green paint within the week. The videotapes were shown to the employees who thought it was hilarious.
If the wall was sufficiently fireproof, I wonder whether sparking devices might be useful?
That’s funny !!!