Kids in my class do graffiti on tables, papers.
Heck that, our
school director even bought them a huge paper (Around the size of 6 humans in lenght, 0.8 in height) and made a graffiti on them.
Here's what
they did:

Personally I hate graffiti. It's bad and you should feel bad.
Also, I wish my camera wasn't so loving stupid, but I ran out of battery right after I took it and I couldn't get the lightning off/on anymore so I was stuck with that lightning flash on it.
However, they tried to make a scaled replica of a graffiti they found on a website I think.