##
0-0 1-0 2-0 3-1
0-0 1-0 2-1 3-1
0-0 1-1 2-1 3-1
##
##
sub enum_area{
my ($x,$y) = split '-', $_[0];
my $minus = $x - $y;
print "$_ " for grep {
my ($cx,$cy) = split '-',$_;
$cy > $cx ? 0 : ( $cx-$cy < $minus + 1 ? 1 : 0)
}
glob '{'.(join ',',0..$x).'}-'.
'{'.(join ',',0..$y).'}';
}