Say you need to generate a sequence, in C++, simply consisting of the first so many integers, like, 1,2,3,4,5.
With a little programming experience, you can come up with a dozen different ways to do this, but here's an obscure one:
std::iota(l.begin(), l.end(), 1);
According to CppReference, the function is named after the integer function ⍳ from the programming language APL.
The more you know.