Suppose there are two spheres freely floating on the surface of an infinitely large and deep body of water. Suppose these two spheres bob up and down independently and create waves (which may or may not have the same frequency and amplitude) in the water. Do these spheres always remain bobbing in a cycle around the same position, or do these wave sources always attract/repel each other? Are there specific conditions to produce attraction/repulsion? (such as a certain phase difference and distance, or matched frequency, etc.) Thanks for any insight.