This page contains ten nested instances of the {{P1}} template, written out indirectly; five nested instances of {{P1}} are given an argument generated using {{User:ais523/P1x5}} (which itself contains five nested instances of {{P1}}).
This is the argument to P1x5.
The "highest expansion depth" for this page is 17, considerably larger than the result obtained by simply writing all the templates out manually.