Wonderful! I love yarn bombing.
There's a village on the coast to the north of Harlech - Llwyngwril - that has been doing this for a long time. We haven't been there for a few years, but they used to have a wonderful, enormous, knitted/crocheted troll living under the bridge at yarn bombing time. And there was one house that had a row of beautifully knitted baby clothes strung along the fence - I could never decide whether they hadn't quite understood what it was about, or they decided that f they were knitting it was going to be something useful!!
I found a picture of him!
There are more pictures of their wonderful knitted things
here, including quite a lot of sheep.