In graffiti, a writer crosses out or paints over another writer's work. This is often done to declare that one writer is more talented or more up than the one being crossed-out. Good graff crews do this to claim territory or beef with a toy crew. It's necessary.
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But really, I like to prefer seeing it more as a collaboration than a competition.

Here are four vibrantly colourful snapshots of ivy growing over a graffiti painted wall. I bet these shots in portrait format will look amazing on a smartphone, but the aspect ratio probably doesn't come across all too well on a desktop monitor and it might not fit your screen on some platforms. Just in case, I've made all the images clickable to be viewed in their full glory at your convenience.

All the above images were shot and processed in RAW. Whitebalance, vignette and highlighting was done in post but the general colours are not artificially altered. Just saying.

Thanks for your upvotes and I'd love to hear your thoughts in the comments below!