use warnings;
use strict;
use 5.10.0;
 
my $x;
 
sub delchar { $x =~ s/(\w)// ?  $1 . delchar() . $1  : "x" }
 
$x='abc';
say delchar();						    #  => "cccxccc"
 
 
  
sub del1 { $x =~ s/(\w)// ? $1 . del2() . $1 : "x"  } 
sub del2 { $x =~ s/(\w)// ? $1 . del3() . $1 : "x"  } 
sub del3 { $x =~ s/(\w)// ? $1 . del4() . $1 : "x"  } 
sub del4 { $x =~ s/(\w)// ? $1 . del5() . $1 : "x"  } 
 
$x='abc';
say del1();                  		    # => "abcxcba"