# return something that is going to come from ... 
# ... an unnamed subroutine (unnamed ... 
# ... because there's nothing between "sub" and "{"
    return sub {

       # r is a random number >= 0 < 1
        my $r = rand();

       # an implicit if statement: 
       # if, when going through every value of odds from lowest ... 
       # ... to highest,  r is less than that value of odds, this ... 
       # ... code will go on to the "and" statement, and otherwise... 
       # ... it will go on to the next value in @odds
       # if it gets to the "and" statement, it will return the ... 
       # ... corresponding value for @vals to the subroutine ... 
       # ... call, which will, in turn, return that to the main ... 
       # body of the script
        $r < $odds[ $_ ] and return $vals[ $_ ] for 0 .. $#odds;

    };