Situate yourself someplace comfortable, then tilt your head back a little bit and look up. Keep looking up and move your gaze from left to right. Notice as many things as you can.
Write about that experience.
Maybe you’ll write a list. You could write about something that surprised you, whether it was what you saw, or what it felt like physically to take in the world from this different line of sight.
Maybe looking up will trigger a memory or some other kind of thought.
When the page is full, give your work a title. Put a signature and the date on it, too.