I have come across an interesting answer here on Physics SE which states that you get standing waves when you throw a rock in a lake, because of an “intrinsic property” of even dimensional waves.
“(...) waves in an even number of dimensions, such as on water, reflect back, even if the wave impedance is constant. For example, if you drop a rock in a lake, the wave does not just circle out leaving the center undisturbed (like a light flash would). Instead, the wave also reflects back and forms a standing wave in the center.”
I have not been able to find more evidence of this phenomenon. What is the best way to interpret this information?