But the paint originally used for the wall or fence might not be available and so another one that doesn't quite match or a completely different shade is used.
The end result often can look like abstract art.
I just love some of the results. Some of these would be good as carpets.
Here's a selection.
Parkhurst Road, N7.
Rowstock Gardens, N7
Rowstock Gardens, N7
Old Street, EC1
Dalston, E8
Bowmans Mews, N7