I've known about lawns being mowed in patterns for years, but didn't really think of it as a hobby, or an art form. It is though. So far I haven't found anything about it, other than how to guides. I would not be surprised if there is a group somewhere for lawn mowing art.

Meanwhile, I'm leaving a link about how to mow your lawn in patterns, from the Spruce site. Seven Common Lawn Mowing Patterns and When to Use Them

Not so related, I found: The Art of LawnMowing by Molly O'Connor, a video post.