How quickly is "quickly"? I've been coding in C++ for years and I still find new ways of doing things and new idioms to consider.
That discussion above does not really apply to C++. But then, if you lower the bar to how much C++ is widely known (the intersection, not union), it'll apply.
From http://www.lysator.liu.se/c/duffs-device.html:
"Somewhere I have a note from dmr [the R in K&R] certifying that all the compilers that he believes in accept it."
So at least at some point Duff showed Ritchie something in C that Ritchie hadn't seen or considered before, long after C had been invented.