DB<103> @hash{$_} = {x=>$x++,y=>$x++} for a..h
 => ""

  DB<112> while ( my ($k1,$v1) = each %hash ) {
            while ( my ($k2,$v2) = each %$v1 ) {
              print "$k1 - $k2 -$v2\n"
            }
          }
e - y -25
e - x -24
a - y -17
a - x -16
d - y -23
d - x -22
... # and so on

##</code><code>##

  DB<106> print Dumper \%hash
$VAR1 = {
          'e' => {
                   'y' => 9,
                   'x' => 8
                 },
          'a' => {
                   'y' => 1,
                   'x' => 0
                 },
          'd' => {
                   'y' => 7,
                   'x' => 6
                 },
          'c' => {
                   'y' => 5,
                   'x' => 4
                 },
...

##</code><code>##

  DB<106> use YAML::Tiny
 => 0

  DB<107> Dump(\%hash) 
---
a:
  x: 16
  y: 17
b:
  x: 18
  y: 19
c:
  x: 20
  y: 21
d:
  x: 22
  y: 23
...