%pair = ( X => 12, Y => 10);

#then keep in a list like this...
$pairlist[0] = \%pair;

##</code><code>##

%pair = (12 => 10);
# no list required, but then (12,10) and then (12,5) wouldn't work...

##</code><code>##

@pair = (12,10);
#with a list assigned like...
$pairlist[0] = \@pair;