Maddy has a go with the paintless spray can
Have you ever painted using a spray can? They're loads of fun to try in art lessons or at home but most street graffiti is illegal.
Now an inventor from Bristol has designed an electronic screen that allows you to spray away without getting into trouble! Maddy's been to find out how....
"The gadget was designed in Bristol where loads of famous graffiti artists started, so we drove around to take a look at some of the brightly coloured walls.
In the Stokes Croft area there are buildings covered in brightly coloured cartoons of people, animals and even outer space!
Maddy tried spraying the Newsround logo
The city's proud of this kind of art, but not all graffiti looks so good.
Slogans sprayed on railway bridges, fences and private buildings count as vandalism, which is against the law.
You're only supposed to get your spray cans out in your own home or on special sites that have been agreed by council officials.
But now there's a chance to do graffiti without any spray paint at all!
Inventors have designed a huge electronic screen to help you do the job. It's powered by a computer and works thanks to a sensor on top of an empty spray can.
You push the button down just as you would do if it was full. You can then select your virtual paint from a huge range of colours as well as choosing how thin or thick you want it.
We watched an expert graffiti artist have a go and the final result was amazing! He managed to paint the Newsround logo in just a few minutes.
Kids who've tried the computer wall told us they find the spray cans easier to use than ordinary cans because they are much lighter. There's also no need to worry about getting your clothes dirty!
The downside is that your graffiti doesn't stick around forever like it does on a wall.
Although you can email your art to yourself so you could post it on a website, use it as a screensaver or print it out to make a poster!
The makers already have plans to put graffiti walls like this in museums and schools, and they're hoping one day you'll be able to buy them in the shops.
I had a go and it was really fun, and definitely very addictive!"