sub popnum3 {
    my ( $x, $y, $z, $offset ) = @_;
    if ( $y == 0 ) {
        $aob[$x][0] = $initial * ( 1 + $z );
    }
    else {
        while (1) {
            $aob[$x][$y] = $aob[$offset][ $y - 1 ] * ( 1 + $z );
            last;
        }
    }
    return $aob[$x][$y];
}