Thanks.<p>FWIW, I wrote &quot;I&#x27;m in mensa&quot; not to brag so much as ... I got in through test scores, and (obviously) have some raw measure of ability in cognitive areas, but still wasn&#x27;t able to immediately get that algorithm from the english.  I get what it means, and understand the implications of the algorithm, but couldn&#x27;t make that immediate jump.  The older I get, the harder it is for me to tell when someone is sharp and maybe just can&#x27;t grasp something immediately, and when they truly can&#x27;t get it.  I probably make more allowances than I did in my youth, precisely because I know my own shortcomings more now than 20 years ago.