I have changed your code:

use Curses;
initscr;
$win = new Curses;
$win->addstr(20, 20, 'Hello');
$win->refresh;
while (1) {};
endwin;
[download]

Update: from here I read:

Window newWin( Int lines, Int cols, Int beginy, Int beginx )
...
lines Number of lines in window
cols Number of columns in window
beginy Position of top of window
beginx Position of left of window
[download]

so the correct form (with function newwin) is:

use Curses;
initscr;
$win = new Curses;
$win = newwin(40,40,1,1);
$win->addstr(20, 20, 'Hello');
$win->refresh;
while (1) {};
endwin;
[download]

Update II: FunkyMonk has just responded before my Update:

(($_="Mzz ojjdloobnf jt uvy5502383")=~y~b-zg2-5c96-81~a-z0-9~s)=~s~~~s; print

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