Or even the famous question &quot;Can you hear the shape of a drum?&quot;, to which we have a constructive proof (under some mathematical idealizations) that the answer is &quot; No&quot;.<p><a href="https:&#x2F;&#x2F;en.m.wikipedia.org&#x2F;wiki&#x2F;Hearing_the_shape_of_a_drum" rel="nofollow">https:&#x2F;&#x2F;en.m.wikipedia.org&#x2F;wiki&#x2F;Hearing_the_shape_of_a_drum</a>