add a new planet!
On the magnetic planet, the particle (a tablet) falls because electromagnetism’s force exponent (if it was modeled like gravity) is slightly higher than 2. This means orbits will either fly away or fall, and the particle just fell. Also, the magnetic planet is held by pure electromagnetism, and you’d float on it because diamagnetism. That water drop is thus floating. Also, people have made apples float via a 45 tesla (T) magnet, as water is VERY diamagnetic IRL, so I’m not just saying this without evidence. Also note that the planet would get magnetized too if the magnet was strong enough. If it was spinning, it would make an electric field and radio waves, and not only would this work well as an "anything in space that was man made" cleaner, it would wreck havoc on your tablet. Also, @griffpatch’s “non-euclidean lemon” project is just an euclidean manifold, as I can see plenty of rectangles with straight line segments.