I&#x27;m sad; I had him for the same course Pachter describes. One time he lectured on the prime number theorem, just for entertainment: he didn&#x27;t prove it, but got deep enough to rather blow me away.<p>Here&#x27;s a more recent elementary talk of his: <a href="http:&#x2F;&#x2F;www.its.caltech.edu&#x2F;~mamikon&#x2F;VisualCalc.html" rel="nofollow">http:&#x2F;&#x2F;www.its.caltech.edu&#x2F;~mamikon&#x2F;VisualCalc.html</a>