Wave pattern 🌊🌊(how my trainer calls it)
So I used do this in trot but if you're not a dressage rider (because it probably won't be a challenge haha) and you're willing to take a challenge doing this in canter is also possible! An exercise that took me a while to learn since I was so lost whenever it comes to "dressage",but eventually I got the hang of it haha. I used to do little dressage tests with my old trainer when we weren't doing flat work or jumping so this pattern (if that's what you call it) really 'leveled up' my "dressage" courses (if that's what you call it again lol I'm so not educated in dressage 😭 please correct me if I get anything very wrong). So personally I still sometimes do this one when warming up during trot because it makes me use my tiny brain and communicate (if thats the word for that) with the horse ❤️
Keep exploring the community!