Untuk tantangan ini, selimut seni ASCII akan menjadi blok teks dengan lebar 24 karakter dan tinggi 18 baris, berisi karakter =-<>/\dalam pola seperti selimut yang simetris secara horizontal dan vertikal.

Contoh selimut:

========================
------------------------
//\\//\\\//\/\\///\\//\\
<<><<>>>>><<>><<<<<>><>>
/\\/\\\\/\/\/\/\////\//\
------------------------
/\/////\\///\\\//\\\\\/\
\///\/\/\\\\////\/\/\\\/
\///\/\/\\\\////\/\/\\\/
/\\\/\/\////\\\\/\/\///\
/\\\/\/\////\\\\/\/\///\
\/\\\\\//\\\///\\/////\/
------------------------
\//\////\/\/\/\/\\\\/\\/
<<><<>>>>><<>><<<<<>><>>
\\//\\///\\/\//\\\//\\//
------------------------
========================

Semua selimut memiliki bentuk yang sama:

• Mereka selalu 24 oleh 18.
• Garis atas (baris 1) dan garis bawah (baris 18) =semuanya berada di seberang.
• Garis 2, 6, 13 dan 17 -semuanya ada di seberang.
• Baris 4 dan 15 adalah acak yang sama secara horizontal simetris pola <dan >.
• Semua baris lainnya (3, 5, 7, 8, 9, 10, 11, 12, 14, 16) diisi dengan /dan dengan \cara yang benar-benar acak sehingga seluruh selimut tetap simetris secara horizontal dan vertikal .

Perhatikan bahwa ketika melipat selimut menjadi dua, baik secara vertikal maupun horizontal, bentuk karakternya benar-benar cocok. Jangan bingung dengan karakter yang cocok. misal jalur 3 dan jalur 16 tidak identik, mereka adalah gambar cermin vertikal.

Tantangan

Tulis program atau fungsi yang akan mencetak atau mengembalikan selimut seni ASCII acak.

Karena banyak garis yang dikodekan dan simetri, satu-satunya keacakan nyata berasal dari 12 karakter pertama pada baris 3, 4, 5, 7, 8, 9:

• 12 karakter pertama pada baris 4 harus bisa sepanjang 12 string karakter <dan> .
• 12 karakter pertama pada baris 3, 5, 7, 8, 9 harus bisa sepanjang 12 string karakter /dan\ (tidak tergantung satu sama lain).
• String acak ini kemudian dicerminkan sesuai untuk membuat seluruh selimut.

Jawaban terpendek dalam byte menang. Tiebreaker adalah posting sebelumnya.

Anda dapat menggunakan generator nomor pseudorandom. (Tidak, Anda tidak perlu membuktikan bahwa ke- 12 string char <>atau /\dapat dihasilkan dengan PRNG bahasa Anda.)

Output secara opsional dapat berisi baris tambahan, tetapi tidak ada spasi tambahan atau karakter lain selain yang diperlukan untuk quilt.

CJam, 61 60 58 55 54 52 51 byte

Dipersingkat sedikit dengan bantuan dari Sp3000 dan Pengoptimal.

"=-/</-///"{C*1{"<\/>"%1$W%\_W%er}:F~+mrC<1FN}%s3F(

Uji di sini.

Penjelasan

Seperti biasa dengan tantangan seni ASCII simetris ini, saya menghasilkan satu kuadran dan kemudian mengembangkannya menjadi dua hal dengan melakukan dua operasi mirroring yang sesuai.

Untuk penjelasan ini saya harus mulai dengan fungsi F, yang saya definisikan di suatu tempat di sepanjang jalan, karena itu digunakan di tiga tempat untuk tiga hal yang berbeda:

{"<\/>"%1$W%\_W%er}:F

Ini mengharapkan integer di bagian atas tumpukan, dan string di bawahnya. Tujuannya adalah membalikkan string dan juga menukar beberapa karakter, untuk mendapatkan mirroring yang tepat. Integer adalah salah satu 1atau 3dan menunjukkan apakah ( 1) tanda kurung dan garis miring harus ditukar atau ( 3) hanya tanda kurung yang ditukar. Inilah cara kerjanya:

"<\/>"            "Push a string with all four relevant characters.";
      %           "% applied to a string and an integer N (in any order) selects every
                   Nth character, starting from the first. So with N = 1 this just
                   leaves the string unchanged, but with N = 3 it returns a string
                   containing only < and >.";
       1$         "Copy the string we want to mirror.";
         W%       "% also takes negative arguments. Giving it -1 reverses the string.";
           \_     "Swap the two strings and duplicate the <\/> or <> string.";
             W%   "Reverse that one. Due to the symmetry of this string, we'll now
                   have the characters to be swapped at corresponding indices.";
               er "Perform element-wise transliteration on the reversed input string
                   to complete the mirroring operation.";

Sekarang untuk sisa kode:

"=-/</-///"                            "This string encodes the 9 different line types.
                                        Note that for the /\ and <> lines we only use
                                        one of the characters. This idea is due to
                                        Sp3000. Thanks! :)";
           {                   }%      "Map this block onto the characters.";
            C*                         "Repeat the character 12 times, turning it into
                                        a string.";
              1{...}:F~                "Define and call F on the resulting string. The
                                        reversal doesn't do anything, but the character
                                        swapping creates strings containing both \/ and
                                        <>.";
                       +mr             "Add the two halves together and shuffle them.";
                          C<           "Truncate to 12 characters. We've now got our
                                        random half-lines.";
                            1F         "Call F again to mirror the half-line.";
                              N        "Push a newline.";
                                 s     "Join all those separate strings together by
                                        converting the array to a string.";
                                  3F   "Perform one more mirroring operation on the
                                        half-quilt, but this time only swap < and >.
                                        This yields the correct full quilt, except
                                        there are two newlines in the centre.";
                                    (  "This slices the leading newline off the second
                                        half and pushes it onto the stack.";

Dua bagian dan baris baru itu kemudian dicetak secara otomatis di akhir program.

Python 3, 257 229 192 185 176 149 143 byte

from random import*
k,*L=80703,
while k:s=eval("''"+".join(sample('--==<>\/'[k%4*2:][:2],2))"*12);L=[s]+L+[s[::(-1)**k]];k//=4
*_,=map(print,L)

Dengan bantuan dari @xnor, kami akhirnya berhasil menyusul JS!

Output sampel:

========================
------------------------
///////////\/\\\\\\\\\\\
>><<<>><<<><><>>><<>>><<
/\/\\/\/\\/\/\//\/\//\/\
------------------------
//\\////\\/\/\//\\\\//\\
/////\\\/\/\/\/\///\\\\\
/\\//\\/////\\\\\//\\//\
\//\\//\\\\\/////\\//\\/
\\\\\///\/\/\/\/\\\/////
\\//\\\\//\/\/\\////\\//
------------------------
\/\//\/\//\/\/\\/\/\\/\/
>><<<>><<<><><>>><<>>><<
\\\\\\\\\\\/\///////////
------------------------
========================

Penjelasan

(Sedikit usang, akan diperbarui nanti)

"444046402"mengkodekan baris, dengan masing-masing digit mengacu pada indeks awal substring 2-char yang relevan dari '--==\/<>'. Setiap baris individu dibangun keluar-masuk melalui pengacakan berulang dari dua karakter (menggunakan sample(...,2), karena random.shufflesayangnya di tempat) dan string bergabung.

Contoh yang disederhanakan dari apa yang terlihat seperti ekspansi untuk baris keempat adalah:

''.join(['<','>']).join(['>','<']).join(['>','<']).join(['<','>']).join(['>','<'])

yang akan menghasilkan ><>><><<><:

               ''
    <>         .join(['<','>'])
   >  <        .join(['>','<'])
  >    <       .join(['>','<'])
 <      >      .join(['<','>'])
>        <     .join(['>','<'])

Selimut keseluruhan juga dibangun di dalam-ke luar, karena konstruksi dimulai dengan baris ke-9 / ke-10, yang bekerja ke luar. Untuk melakukan ini kita mulai dengan daftar kosong L, yang kita tambahkan baris ke depan dan belakang saat kita pergi

L=[s]+L+[[s,s[::-1]][n<"5"]]

The n<"5"kondisi adalah untuk memeriksa apakah kita memiliki baris yang terdiri dari ><, dalam hal ini kita menambahkan sebuah baris identik ke belakang, sebaliknya yang terbalik.

Akhirnya, *_,=adalah untuk memaksa evaluasi mapsehingga pencetakan terjadi, dan hanya cara yang lebih singkat untuk dilakukan print("\n".join(L)).

Untuk waktu yang lama saya memiliki fungsi

g=lambda s:s.translate({60:62,62:60,92:47,47:92})

yang mengambil string dan mengkonversi masing /\><- \/<>masing, tetapi saya akhirnya berhasil menyingkirkannya :)

Python 2, 300 byte

Program ini menggunakan join, lambda, replace, sample, importdan fungsi verbose lainnya, sehingga tidak akan memenangkan penghargaan golf apa pun.

from random import*
f=lambda a,b,t:t.replace(a,'*').replace(b,a).replace('*',b)
k=lambda a:''.join(sample(a*12,12))
c='-'*24
e=k('<>')
h=e+f('<','>',e[::-1])
j=[d+f('/','\\',d[::-1])for d in[k('\\/')for i in'quilt']]
g=['='*24,c,j[0],h,j[1],c]+j[2:]
print'\n'.join(g+[f('/','\\',d)for d in g[::-1]])

Kode sebelum pegolf otomatis mengambilnya:

from random import *

change = lambda a,b,t: t.replace(a,'*').replace(b,a).replace('*',b)
pick = lambda a: ''.join(sample(a*12, 12))

innerline = '-' * 24
line4h = pick('<>')
line4 = line4h + change('<', '>', line4h[::-1])
diag = [d + change('/', '\\', d[::-1]) for d in [pick('\\/') for i in 'quilt']]

quilt = ['='*24, innerline, diag[0], line4, diag[1], innerline] + diag[2:]
print '\n'.join(quilt + [change('/', '\\', d) for d in quilt[::-1]])

Output sampel:

========================
------------------------
\\\\/\////\\//\\\\/\////
<><<>>>><><><><><<<<>><>
/\\\\////\\\///\\\\////\
------------------------
\\\\//\///\\//\\\/\\////
//\//\\\\/\/\/\////\\/\\
\/\\\\/\//\/\/\\/\////\/
/\////\/\\/\/\//\/\\\\/\
\\/\\////\/\/\/\\\\//\//
////\\/\\\//\\///\//\\\\
------------------------
\////\\\\///\\\////\\\\/
<><<>>>><><><><><<<<>><>
////\/\\\\//\\////\/\\\\
------------------------
========================

APL (53 58)

It's not quite as symmetrical as I thought it was, unfortunately. Fix cost me 5 characters and now I'm out of the running.

L←+,3-⌽⋄'==--/\<><'[↑(732451451260688⊤⍨18/8)+L{L?12⍴2}¨⍳9]

Explanation:

• L←+,3-⌽: L is a function that returns its argument followed by 3 - the reverse of its argument
• L{L?12⍴2}¨⍳9: generate 9 lines of 12 random values from [1,2] plus their reverse, then the reverse of those 9 lines
• 732451451260688⊤⍨18/8: generate the list 0 2 4 6 4 2 4 4 4 4 4 4 2 4 _7_ 4 2 0 (that's where the damn asymmetricality is)
• +: for each line, add the corresponding number to each value
• ↑: format as matrix
• '==--/\<><'[...]: for each of the numbers in the matrix, select the character from the string at that position

Output:

========================
------------------------
///////\\///\\\//\\\\\\\
<<><<><><<<<>>>><><>><>>
\\\\\//\/\\\///\/\\/////
------------------------
/\///\\/\/\/\/\/\//\\\/\
\////////\//\\/\\\\\\\\/
\\/\\\//\///\\\/\\///\//
//\///\\/\\\///\//\\\/\\
/\\\\\\\\/\\//\////////\
\/\\\//\/\/\/\/\/\\///\/
------------------------
/////\\/\///\\\/\//\\\\\
<<><<><><<<<>>>><><>><>>
\\\\\\\//\\\///\\///////
------------------------
========================

PHP, 408, 407, 402, 387, 379 bytes

I am not a good golfer, but this problem sounded fun so I gave it a try.

<?$a=str_replace;$b=str_repeat;function a($l,$a,$b){while(strlen($s)<$l){$s.=rand(0,1)?$a:$b;}return$s;}$c=[$b('=',12),$b('-',12),a(12,'/','\\'),a(12,'<','>'),a(12,'/','\\'),$b('-',12)];while(count($c)<9){$c[]=a(12,'/','\\');}for($d=9;$d--;){$c[$d].=strrev($a(['/','<','\\','>',1,2],[1,2,'/','<','\\','>'],$c[$d]));$c[]=$a(['/','\\',1],[1,'/','\\'],$c[$d]);}echo implode("
",$c);

Ungolfed code

<?php

    function randomString($length, $a, $b) {
        $string = '';
        while(strlen($string) < $length) {
            $string .= rand(0, 1) ? $a : $b;
        }
        return $string;
    }

    if(isset($argv[1])) {
        srand(intval($argv[1]));
    }

    $lines = [
        str_repeat('=', 12),
        str_repeat('-', 12),
        randomString(12, '/', '\\'),
        randomString(12, '<', '>'),
        randomString(12, '/', '\\'),
        str_repeat('-', 12)
    ];
    while(count($lines) < 9) {
        $lines[] = randomString(12, '/', '\\');
    }

    for($index = count($lines); $index--;) {
        $lines[$index] .= strrev(str_replace(['/', '<', '\\', '>', 1, 2], [1, 2, '/', '<', '\\', '>'], $lines[$index]));
        $lines[] = str_replace(['/', '\\', 1], [1, '/', '\\'], $lines[$index]);
    }

    echo implode("\n", $lines) . "\n";

?>

The ungolfed version has a little bonus: You can pass it an integer to seed rand() and get the same quilt each time for a seed:

php quilt.php 48937

This results, for example, in this beautiful, hand woven quilt:

========================
------------------------
/\\\////\\\/\///\\\\///\
><>><>><<<><><>>><<><<><
/\\\///\//\/\/\\/\\\///\
------------------------
/\\/\\\/\\/\/\//\///\//\
/\\\\/\//\\/\//\\/\////\
\/\\/\/\////\\\\/\/\//\/
/\//\/\/\\\\////\/\/\\/\
\////\/\\//\/\\//\/\\\\/
\//\///\//\/\/\\/\\\/\\/
------------------------
\///\\\/\\/\/\//\///\\\/
><>><>><<<><><>>><<><<><
\///\\\\///\/\\\////\\\/
------------------------
========================

Edit: Turns out my first version did not return a correct quilt. So I fixed it. Funny enough, the fix is even shorter.

JavaScript (ES6) 169 195 201

Edit 6 bytes saved thx @nderscore. Beware, the newline inside backquotes is significant and counted.

Edit2 simplified row building, no need of reverse and concat

F=(o='')=>[...z='/\\/-/<\\-='].map((c,i,_,y=[z,'\\/\\-\\>/-='],q=[for(_ of-z+z)Math.random(Q=k=>q.map(v=>r=y[v^!k][i]+r+y[v^k][i],r='')&&r+`
`)*2])=>o=Q()+o+Q(i!=5))&&o

Run snippet to test (in Firefox)

F=(o='')=>[...z='/\\/-/<\\-='].map((c,i,_,y=[z,'\\/\\-\\>/-='],q=[for(_ of-z+z)Math.random(Q=k=>q.map(v=>r=y[v^!k][i]+r+y[v^k][i],r='')&&r+`
`)*2])=>o=Q()+o+Q(i!=5))&&o

Q.innerHTML=F()

<pre id=Q style='font-size:9px;line-height:9px'>

Ruby, 162 155

I like this one because it made me learn to abuse backslashes in both string literals and String#tr. The code isn't terribly clever otherwise, just compact.

a='/\\'
b='\\\/'
t=Array.new(9){x=''
12.times{x+=a[rand(2)]}
x+x.reverse.tr(a,b)}
t[0]=?=*24
t[1]=t[5]=?-*24
t[3].tr!a,'<>'
puts t,((t.reverse*'
').tr a,b)

Pyth, 57 59 61

J"\<>/"K"\/"L+b_mXdK_Kbjbym+d_XdJ_JmsmOk12[\=\-K-JKK\-KKK

J"\<>/"K"\/"jbu++HGXHK_Km+d_XdJ_JmsmOk12[KKK\-K-JKK\-\=)Y

Thanks a lot to @Jakube for coming up with these 57 byte versions.

Algorithm very similar to Martin's. (Revised) Explanation to come.

Try it online

Explanation:

=G"\<>/"                            : Set G to be the string "\<>/"
K"\/"                               : Set K to be the string "\/"
Jm+d_XdG_GmsmOk12[\=\-K"<>"K\-KKK;  : Set J to be the top half of the carpet
                 [\=\-K"<>"K\-KKK;  : Make a list of possible chars for each row
          msmOk12                   : for each element of that list,
                                    : make a list of 12 randomly chosen characters
                                    : from it, then join them
Jm+d_XdG_G                          : for each element of that list,
                                    : make a new list with the old element,
                                    : and its horizontal reflection
jb+J_mXdK_KJ                        : Print the whole carpet
     mXdK_KJ                        : For each element of J make its vertical reflection

J, 56 54 bytes

'=/\<>--></\'{~(-,|.)0,(3(2})8$5,3#1)+(,1-|.)"1?8 12$2

Usage:

   '=/\<>--></\'{~(-,|.)0,(3(2})8$5,3#1)+(,1-|.)"1?8 12$2
========================
------------------------
///\\\\/\///\\\/\////\\\
><<><><>><>><<><<><><>><
\\/\//\\/\//\\/\//\\/\//
------------------------
\/\/\//////\/\\\\\\/\/\/
/\/\\//\//\\//\\/\\//\/\
//\\\\/////\/\\\\\////\\
\\////\\\\\/\/////\\\\//
\/\//\\/\\//\\//\//\\/\/
/\/\/\\\\\\/\//////\/\/\
------------------------
//\/\\//\/\\//\/\\//\/\\
><<><><>><>><<><<><><>><
\\\////\/\\\///\/\\\\///
------------------------
========================

1 byte thanks to @FUZxxl.

Explanation coming soon.

Try it online here.

Python 295 287 227 bytes

Not that great but I'll post it anyway:

from random import*
m,d=[],dict(zip("\/<>=-","/\><=-"))
v=lambda w:[d[x]for x in w]
for e in '=-/>/-///':f=[choice([e,d[e]])for x in[0]*12];t=''.join(f+v(f[::-1]));print t;m+=''.join(e=='/'and v(t)or t),
print'\n'.join(m[::-1])

If you want an explanation just ask me.

Javascript (ES7 Draft) 174 168 146

Some inspiration taken from @edc65

Edit: Thanks to edc65 for some ideas to optimize building of rows.

F=(o='')=>[for(i of'555357531')(z=[for(_ of c='==--/\\<>golf')Math.random(r=x=>z.reduce((s,y)=>c[w=i^y^x]+s+c[w^1],'')+`
`)*2],o=r()+o+r(i<7))]&&o

Demonstration: (Firefox only)

F=(o='')=>[for(i of'555357531')(z=[for(_ of c='==--/\\<>golf')Math.random(r=x=>z.reduce((s,y)=>c[w=i^y^x]+s+c[w^1],'')+`
`)*2],o=r()+o+r(i<7))]&&o

document.write('<pre>' + F() + '</pre>');

Commented:

// define function, initialize output to ''
F = (o = '') =>
    // loop through character indexes of first 9 lines
    [
        for (i of '555357531')(
            // build array of 12 random 0/1's, initialize character list
            z = [
                for (_ of c = '==--/\\<>golf')
                    Math.random(
                        // define function for generating lines
                        // if x is true, opposite line is generated
                        r = x =>
                            z.reduce(
                                (s, y) => 
                                    c[w = i ^ y ^ x] + s + c[w ^ 1],
                                ''
                            ) + `\n`
                    ) * 2
            ],
            // build new lines and wrap output in them
            // x true in the second line for indexes < 7 (not character '>')
            o = r() + o + r(i < 7)
        )
    ]
    // return output
    && o

Pharo 4, 236

|s i f v h|s:='====----/\/\/<><<>'.f:=[:c|s at:(s indexOf:c)+i].v:=#(),'=-/</-///'collect:[:c|h:=(String new:12)collect:[:x|i:=2atRandom.f value:c].i:=1.h,(h reverse collect:f)].i:=3.String cr join:v,(v reverse collect:[:k|k collect:f])

or formatted normally:

|s i f v h|
s:='====----/\/\/<><<>'.
f:=[:c|s at:(s indexOf:c)+i].
v:=#() , '=-/</-///'
  collect:[:c|
    h:=(String new:12)collect:[:x|i:=2atRandom.f value:c].
    i:=1.
    h,(h reverse collect:f)].
i:=3.
String cr join:v,(v reverse collect:[:k|k collect:f])

Explanation:

The string s:='====----/\/\/<><<>' together with the block f:=[:c|s at:(s indexOf:c)+i] are here both for tossing the characters and for reversing the patterns...

• For i=1, it performs horizontal reversion (/ <-> \ , < <-> > ).

• For i=3, it performs vertical reversion (/ <-> \)

• For i=1 or 2 atRandom, it toss among / or \, < or >

'=-/</-///' encodes the character type c that will feed the block f for the 9 first lines.

#() , '=-/</-///' is a concatenation trick for transforming the String into an Array and thus collecting into an Array.

The rest is simple concatenation after applying the horizontal/vertical symetry.

========================
------------------------
\\/\/\\\\/\/\/\////\/\//
>>>><><><>><><<><><><<<<
\/\/\//\///\/\\\/\\/\/\/
------------------------
/\//\/\/////\\\\\/\/\\/\
\\//\//\\\/\/\///\\/\\//
////\\/\/\//\\/\/\//\\\\
\\\\//\/\/\\//\/\/\\////
//\\/\\///\/\/\\\//\//\\
\/\\/\/\\\\\/////\/\//\/
------------------------
/\/\/\\/\\\/\///\//\/\/\
>>>><><><>><><<><><><<<<
//\/\////\/\/\/\\\\/\/\\
------------------------
========================

Squeak 4.X, 247

|r s h m n p|s:='==--/\<>'.r:=(1<<108)atRandom.h:=''.m:=0.(16to:0by:-2),(0to:16by:2)do:[:i|n:=3bitAnd:28266>>i.p:=0.(11to:0by:-1),(0to:11)do:[:j|h:=h,(s at:n*2+1+(r-1>>(6*i+j)+(101>>(3-n*4+m+p))bitAnd:1)).j=0and:[p:=1]].i=0and:[m:=2].h:=h,#[13]].h

Or formatted:

|r s h m n p|
s:='==--/\<>'.
r:=(1<<108)atRandom.
h:=''.
m:=0.
(16to:0by:-2),(0to:16by:2) do:[:i|
  n:=3 bitAnd: 28266>>i.
  p:=0.
  (11to:0 by:-1),(0to:11) do:[:j|
    "h:=h,(s at:n*2+1+((r-1bitAt:6*i+j+1)bitXor:(101bitAt:3-n*4+m+p))). <- originally"
    h:=h,(s at:n*2+1+(r-1>>(6*i+j)+(101>>(3-n*4+m+p))bitAnd:1)).
    j=0and:[p:=1]].
  i=0and:[m:=2].
  h:=h,#[13]].
h

Explanations:

s:='==--/\<>'. obviously encodes the four posible pairs.

r:=(1<<108)atRandom. toss 108 bits (in a LargeInteger) for 9 rows*12 columns (we toss the == and -- unecessarily but performance is not our problem).

h:=''is the string where we will concatenate (Schlemiel painter because a Stream would be too costly in characters).

(16to:0by:-2),(0to:16by:2)do:[:i| is iterating on the rows (*2)

(11to:0by:-1),(0to:11) do:[:j| is iterating on the columns

28266 is a magic number encoding the pair to be used on first 9 lines.
It is the bit pattern 00 01 10 11 10 01 10 10 10, where 00 encodes '==', 01 '--', 10 '/\' and 11 '<>'.

101 is a magic number encoding the horizontal and vertical reversion.
It is the bit pattern 0000 0000 0110 1010, encoding when to reverse (1) or not (0) the first (0) or second (1) character of each pair '==' '--' '/\' and '<>', for the vertical symetry and horizontal symetry.

n:=3 bitAnd: 28266>>i gives the encoding of character pair for row i/2 (0 for '==', 1 for '--', 2 for '/\' and 3 for '<>').

(r-1 bitAt: 6*i+j+1) pick the random bit for row i/2 column j (1 is the rank of lowest bit thus we have a +1, k atRandom toss in interval [1,k] thus we have a -1).

(101 bitAt: 3-n*4+m+p) pick the reversal bit: (3-n)*4 is the offset for the group of 4 bits corresponding to the pair code n, m is the vertical reversion offset (0 for first 9, 2 for last 9 rows), p is the horizontal reversion offset (0 for first 12, 1 for last 12 columns)+1 because low bit rank is 1.

bitXor: performs the reversion (it answer an offset 0 or 1), and s at:2*n+1+bitXor_offset pick the right character in s.

But (A>>a)+(B>>b) bitAnd: 1 costs less bytes than (A bitAt:a+1)bitXor:(B bitAt:b+1)thus the bitXor was rewritten and offset +1 on p is gone...

h,#[13] is an ugly squeakism, we can concatenate a String with a ByteArray (containing code for carriage return).

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