$things{ $thing }{$someotherkey}[$someindex]{$somekey}[ $_ ] = $things{ $thing }{$someotherkey}[$someindex]{$somekey}[ $_ ] + 1 % 10 for 1 .. 10;

##</code><code>##

@{ $things{ $thing }{$someotherkey}[$someindex]{$somekey} }[ 1 .. 10 ] = map{ ++$_ % 10 } @{ $things{ $thing }{$someotherkey}[$someindex]{$somekey} }[ 1 .. 10 ];