These days I'm also very slowly reading Jeanette Winterson - a few pages each day. I get stopped by the wonderful imagery she is able to bring up in my imagination. Here's another passage from her Oranges are not novel:
Magic was very important.
The chalk circle you drew around yourself to protect yourself from elementals and the like.
It's gone out of fashion now, which is a shame.
Of course people will laugh at you, but people laugh at a great many things, so there's no need to take it personally.
Why will it work?
It works because the principle of personal space is always the same. It's a force field around yourself, and as long as our imagining powers are weak, it's useful to have something physical to remind us.