my ($start,$stop,$min) = @_;
  my $tier = $min;
  my ($bin_start,$bin_end);
  while (1) {
    $bin_start = int $start/$tier;
    $bin_end   = int $stop/$tier;
    last if $bin_start == $bin_end;
    $tier *= 10;
  }
  return wantarray ? ($tier,$bin_start) : bin_name($tier,$bin_start);

  my $tier = shift;
  my $pos  = shift;
  bin_name($tier,int($pos/$tier));

 sprintf("%d.%06d",@_)

  my $i = shift;
  log($i)/log(10);