my @cols = 0..11;
randomly_derange( \@cols );
@nums = map [ @{$_}[@cols] ], @nums;

sub randomly_derange {
  my $arr = shift();
  my @i = 0..$#$arr;
  while ( @i ) {
    my @swap = map splice( @i, rand( @i ), 1 ), 1, 2;
    @{ $arr }[ @swap ] = @{ $arr }[ @swap[ 1, 0 ] ];
    last if @i == 3;
  }
  if ( @i ) {
    my @j = rand() < 0.5 ? @i[ 1, 2, 0 ] : @i[ 2, 0, 1 ];
    @{ $arr }[ @i ] = @{ $arr }[ @j ];
  }
}