sub tick { my $self = shift; my $cells = $self->{Cells}; my ( $k1, $k2, $k3, $k4, $k5, $k6, $k7, $k8, $x0, $x1, $x2, $y0, $y1, $y2 ); %{$cells} = map { ( $x0, $y0 ) = unpack 'i2', $_; ( $x1, $x2, $y1, $y2 ) = ( $x0 - 1, $x0 + 1, $y0 - 1, $y0 + 1 ); my @zcells = ( ($k1 = pack 'i2', $x1, $y1) x !exists($cells->{$k1}), ($k2 = pack 'i2', $x1, $y0) x !exists($cells->{$k2}), ($k3 = pack 'i2', $x1, $y2) x !exists($cells->{$k3}), ($k4 = pack 'i2', $x0, $y1) x !exists($cells->{$k4}), ($k5 = pack 'i2', $x0, $y2) x !exists($cells->{$k5}), ($k6 = pack 'i2', $x2, $y1) x !exists($cells->{$k6}), ($k7 = pack 'i2', $x2, $y0) x !exists($cells->{$k7}), ($k8 = pack 'i2', $x2, $y2) x !exists($cells->{$k8}) ); ($_, undef) x (@zcells == 5 || @zcells == 6), map { ( $x0, $y0 ) = unpack 'i2', $_; ( $x1, $x2, $y1, $y2 ) = ( $x0 - 1, $x0 + 1, $y0 - 1, $y0 + 1 ); ($_, undef) x ( exists($cells->{pack 'i2', $x1, $y1}) + exists($cells->{pack 'i2', $x1, $y0}) + exists($cells->{pack 'i2', $x1, $y2}) + exists($cells->{pack 'i2', $x0, $y1}) + exists($cells->{pack 'i2', $x0, $y2}) + exists($cells->{pack 'i2', $x2, $y1}) + exists($cells->{pack 'i2', $x2, $y0}) + exists($cells->{pack 'i2', $x2, $y2}) == 3 ) } @zcells } keys %{$cells}; }