This software has a very human-like way to read numbers. Imagine if a computer may read numbers in single digits only.
Example:
1
What do you see in the line above?
Your answer should be "a one" or to be more precise "one (number) one".
11
Now how would you read the line above if you'd only have to use single digits number?
That's "two ones".
21
And how would you read this number?
It's "one two (and) one one".
1211
....
At this point you should have understood the way this algorithm works. You provide an initial number 'n', which is the number the whole algorithm will start on. And the number of iterations 'iter', which defines how many times the software will read the line above.
FUN FACT: 22 is a special number which will repeat itself for ever.