initial commitHEADmain

15 files changed, 882 insertions, 0 deletions

diff --git a/1-sliding-puzzle/authors.markdown b/1-sliding-puzzle/authors.markdown
new file mode 100644
index 0000000..f308e56
--- /dev/null
+++ b/1-sliding-puzzle/authors.markdown
@@ -0,0 +1,3 @@
+* Kensuke Imamura (@nsfisis)
+    * nsfisis@gmail.com
+    * cctld: jp
diff --git a/1-sliding-puzzle/entry.pretty.rb b/1-sliding-puzzle/entry.pretty.rb
new file mode 100644
index 0000000..80e493e
--- /dev/null
+++ b/1-sliding-puzzle/entry.pretty.rb
@@ -0,0 +1,80 @@
+$b = 'bcdefghia';
+eval($s='
+t = {
+  h: [1, 0],
+  j: [0, -1],
+  k: [0, 1],
+  l: [-1, 0],
+  i: [0, 0]
+};
+p = -> a, b {
+  i = $b.index(?a);
+  x = i % 3 + a;
+  y = i / 3 + b;
+  (x < 0 || 2 < x || y < 0 || 2 < y) ||
+    ($b[j = y * 3 + x], $b[i] = $b[i], $b[j])
+};
+i = (o = :"#{$*[0]}") == :i;
+while (o != :q);
+  if (q = t[o]);
+    p[*q];
+  else;
+    (o = o.to_s.to_i) > 0 && (
+      srand(o);
+      a = b = n = 45;
+      (p[*(a, b = (t.values - [[-a, -b], [0, 0]]).sample)] && n -= 1) while (n > 0);
+    );
+  end;
+  print("$b=\47#$b\47;eval($s=\47");
+  n = "1111141424414143341142414424344111143434".scan(/.{,5}/);
+  m = "000001100101111".scan(/.{,3}/);
+  s = 0;
+  b = -> _ = 1 {_.times{print($s[(s += 1) - 1])}};
+  w = -> _ = 13 {print "\40" * _};
+  b[22];
+  puts;
+  3.times {|y|
+    b[45];
+    puts;
+    b[2];
+    w[];
+    b[];
+    w[];
+    b[];
+    w[];
+    b[2];
+    puts;
+    10.times {|l|
+      b[2];
+      3.times {|x|
+        w[2];
+        $b[y * 3 + x] == ?a ? (
+          (l == 3 && !print("\40\40\124\122\111\103\113\40\40")) ||
+          (l == 5 && !print("\105\120\111\123\117\104\105\40\111")) ||
+          w[9]
+        ) :
+          m[n[$b[y * 3 + x].ord - 98][l / 2].to_i].chars{(_1 == ?1 ? b : w)[3]};
+        w[2];
+        b[x / 2 + 1]
+      };
+      puts
+    };
+    b[2];
+    w[];
+    b[];
+    w[];
+    b[];
+    w[];
+    b[2];
+    puts;
+    b[45];
+    puts
+  };
+  b[9];
+  puts("\47.gsub(/[[:space:][:upper:]]/,%%%));");
+  i ||
+    break;
+  print("\12enter\40[hjkl]\40or\40[q]uit\40>\40");
+  o = :"#{$stdin.gets.chomp}";
+  puts;
+end'.gsub(/[[:space:][:upper:]]/,%%%));
diff --git a/1-sliding-puzzle/entry.rb b/1-sliding-puzzle/entry.rb
new file mode 100644
index 0000000..2f3f31e
--- /dev/null
+++ b/1-sliding-puzzle/entry.rb
@@ -0,0 +1,44 @@
+$b='bcdefghia';eval($s='t={h:[1,0],j:[0,-1],k:
+[0,1],l:[-1,0],i:[0,0]};p=->a,b{i=$b.index(?a
+);             x             =             i%
+3+        a;y  =  i/3+b;(x<  0  ||2<x||y<  0|
+|2        <y)  |  |($b[j=y*  3  +x],$b[i]  =$
+b[        i],  $        b[j  ]        )};  i=
+(o        =:"  #        {$*  [        0]}  ")
+==        :i;  w  hile(o!=:  q  );if(q=t[  o]
+);        p[*  q  ];else;(o  =  o.to_s.to  _i
+)>        0&&  (  sra        n        d(o  );
+a=        b=n  =  45;        (        p[*  (a
+,b        =(t  .  values-[[  -  a,-b],[0,  0]
+])        .sa  m  ple)]&&n-  =  1)while(n  >0
+);             )             ;             en
+d;print("$b=\47#$b\47;eval($s=\47");n="111114
+1424414143341142414424344111143434".scan(/.{,
+5}             /             )             ;m
+="  000   001  1  00101111"  .  scan(/.{,  3}
+/)  ;s=   0;b  =  ->_=1{_.t  i  mes{print  ($
+s[  (s+   =1)  -  1])        }  };w        =-
+>_  =13   {pr  i  nt"        \  40"        *_
+};  b[22];put  s  ;3.times{  |  y|b[45];p  ut
+s;  b[2];w[];  b  [];w[];b[  ]  ;w[];b[2]  ;p
+ut        s;1  0        .ti  m  es{   |l|  b[
+2]        ;3.  t        ime  s  {|x   |w[  2]
+;$        b[y  *  3+x]==?a?  (  (l==3&&!p  ri
+nt        ("\  4  0\40\124\  1  22\111\10  3\
+11             3             \             40
+\40"))||(l==5&&!print("\105\120\111\123\117\1
+04\105\40\111"))||w[9]):m[n[$b[y*3+x].ord-98]
+[l             /             2             ].
+to  _i].chars  {  (_1==?1?b  :             w)
+[3  ]};w[2];b  [  x/2+1]};p  u             ts
+};        b[2  ]  ;w[   ];b  [             ];
+w[        ];b  [  ];w   [];  b    TRICK    [2
+];        put  s  ;b[45];pu  t             s}
+;b        [9]  ;  puts("\47  .  EPISODE I  gs
+ub        (/[  [  :sp   ace  :             ][
+:u        ppe  r  :]]   /,%  %             %)
+);        ");  i  ||break;p  r             in
+t(        "\1  2  enter\40[  h             jk
+l]             \             4             0o
+r\40[q]uit\40>\40");o=:"#{$stdin.gets.chomp}"
+;puts;end'.gsub(/[[:space:][:upper:]]/,%%%));
diff --git a/1-sliding-puzzle/remarks.markdown b/1-sliding-puzzle/remarks.markdown
new file mode 100644
index 0000000..c5bb8ae
--- /dev/null
+++ b/1-sliding-puzzle/remarks.markdown
@@ -0,0 +1,90 @@
+# 3x3 Sliding Puzzle Quine
+
+
+
+## Remarks
+
+This is a quine-like program.
+
+When run without arguments, it outputs `entry.rb` itself:
+
+```
+$ ruby entry.rb
+$ ruby entry.rb | ruby
+$ ruby entry.rb | ruby | ruby
+```
+
+It has been tested with the following environment:
+
+```
+$ ruby --version
+ruby 3.4.1 (2024-12-25 revision 48d4efcb85) +PRISM [x86_64-linux]
+```
+
+
+
+## Description
+
+This program is not only a quine but also a 3x3 sliding puzzle.
+
+
+### How to Play
+
+You can move a tile adjacent to the empty slot using `h` (left), `j` (down), `k` (up), `l` (right).
+For example:
+
+```
+$ ruby entry.rb l
+```
+
+This command moves `8` to right.
+Of course, the output source code is still a quine. These two commands' output are identical:
+
+```
+$ ruby entry.rb l
+$ ruby entry.rb l | ruby
+```
+
+
+### How to Shuffle
+
+You can shuffle the board by passing a seed as an argument:
+
+```
+$ ruby entry.rb 2025
+```
+
+The output puzzle can be solved using the following move sequence:
+
+```
+$ ruby entry.rb 2025 | \
+    ruby - k | ruby - l | ruby - k | ruby - j | ruby - h | \
+    ruby - j | ruby - l | ruby - k | ruby - h | ruby - j | \
+    ruby - h | ruby - l | ruby - k | ruby - k | ruby - l | \
+    ruby - j | ruby - h | ruby - h | ruby - k | ruby - j | \
+    ruby - l | ruby - l | ruby - k | ruby - h | ruby - h > solved.rb
+$ diff entry.rb solved.rb
+```
+
+
+### Interactive mode
+
+In addition, it supports interactive mode. Simply run:
+
+```
+$ ruby entry.rb i
+```
+
+It will display the current board and ask for your next move.
+You can exit by typing `q` in interactive mode.
+
+
+
+## Internals
+
+* `entry.pretty.rb` is a human-readable version.
+* `$b` represents the board's current state.
+* `$s` is the program's own source code for quine generation. It contains no "padding" characters, such as unnecessary parentheses, semicolons, or comments.
+* Font data is encoded in the variables `n` and `m`.
+* The string "TRICK EPISODE I" shown in the empty slot is removed using `gsub(/[[:upper:]]/)`. This works because there are no uppercase letters in `$s` except for that.
+* The size of the `entry.rb` is 2025 byte.
diff --git a/2-the-false-awakens/authors.markdown b/2-the-false-awakens/authors.markdown
new file mode 100644
index 0000000..f308e56
--- /dev/null
+++ b/2-the-false-awakens/authors.markdown
@@ -0,0 +1,3 @@
+* Kensuke Imamura (@nsfisis)
+    * nsfisis@gmail.com
+    * cctld: jp
diff --git a/2-the-false-awakens/entry.clean.rb b/2-the-false-awakens/entry.clean.rb
new file mode 100644
index 0000000..9a3ce0b
--- /dev/null
+++ b/2-the-false-awakens/entry.clean.rb
@@ -0,0 +1,100 @@
+# A long time ago in a galaxy far,
+# far away....
+
+
+
+
+
+
+
+eval(%w{
+
+def'false(p,s=[],v={});
+  c=0;
+  while(c<p.size);
+    if(!(i=p[c]));false;
+    elsif"$"==i;s.push(s.last);
+    elsif"%"==i;s.pop;
+    elsif(28.chr)==i;s.push(s.pop,s.pop);
+    elsif"@"==i;s[-3],s[-2],s[-1]=s[-2],s[-1],s[-3];
+    elsif"+"==i;s.push(s.pop+s.pop);
+    elsif"-"==i;s.push(-s.pop+s.pop);
+    elsif"*"==i;s.push(s.pop*s.pop);
+    elsif"/"==i;s.push(s.pop.then{s.pop/_1});
+    elsif"_"==i;s.push(-s.pop);
+    elsif"&"==i;s.push(s.pop&s.pop);
+    elsif"|"==i;s.push(s.pop|s.pop);
+    elsif"~"==i;s.push(~s.pop);
+    elsif">"==i;s.push((s.pop<s.pop)?~0:0);
+    elsif"="==i;s.push((s.pop==s.pop)?~0:0);
+    elsif"!"==i;self.false(s.pop,s,v);
+    elsif"?"==i;s.pop.then{s.pop!=0&&self.false(_1,s,v)};
+    elsif":"==i;v[s.pop]=s.pop;
+    elsif";"==i;s.push(v[s.pop]);
+    elsif","==i;print(s.pop.chr);
+    elsif"."==i;print(s.pop);
+    elsif/[0-9]/=~i;s.push(i.to_i);
+    elsif/[a-z]/=~i;s.push(i);
+    elsif"["==i;
+      q=c+=(b=1);
+      while(b!=0);
+        b+={"["=>1,"]"=>-1}[p[c]]||0;
+        c+=1;
+      end;
+      s.push(p[q...(c-=1)]);
+    elsif"#"==i;
+      a,b=s.pop,s.pop;
+      loop{;
+        self.false(b,s,v);
+        s.pop!=0&&break;
+        self.false(a,s,v);
+      };
+    end;
+    c+=1;
+  end;
+end;
+
+
+class'String;
+  def&(other);
+    (self[1..]+other[1..])
+      .chars
+      .map{(_1.upcase==_1)??1:?0}
+      .join
+      .to_i(2)
+      .chr;
+  end;
+
+  def|(other);
+    (self||"")+(other||"");
+  end;
+
+  def'method_missing(_);
+    self;
+  end;
+end;
+
+
+def'Object.const_missing(n);
+  const_set(n,n.to_s);
+end;
+
+}.join.gsub("'"," "))
+
+
+
+
+     EPISODE_VII
+
+  THE_FALSE_AWAKENS
+
+
+
+
+self.false((
+  May.the.false.be.with.you;
+  TrUE&FaLsE|TrUe&FaLse|TrUe&FAlSe|TrUE&FalSE|TrUe&FAlSe|TrUe&FaLse|TrUe&FaLse|TrUe&FaLse|TrUe&FaLse|TrUE&FAlsE|TrUe&FAlSE|TrUe&FALse|
+  TrUE&FaLSE|TrUe&FAlSE|TrUe&FALse|TrUE&FalSe|TrUe&FALsE|TrUe&FALse|TrUE&FAlse|TrUe&FALsE|TrUe&FALse|TrUe&FALse|TrUE&FaLse|TrUE&FAlse|
+  TrUe&FAlSe|TrUe&FALse|TrUE&FaLsE|TrUE&FalSe|TrUE&False|TrUE&FalSe|TrUe&FALSe|TrUe&FALSe|TrUe&FALSe|TrUe&FALSe|TrUE&FalSe|TrUE&FaLsE|
+  TrUe&FAlSe|TrUe&FALse|false
+))
diff --git a/2-the-false-awakens/entry.rb b/2-the-false-awakens/entry.rb
new file mode 100644
index 0000000..199d42a
--- /dev/null
+++ b/2-the-false-awakens/entry.rb
@@ -0,0 +1,57 @@
+# A long time ago in a galaxy far,
+# far away....
+
+
+
+
+
+
+
+eval(%w{def'false(p,s=[],v={});c=0;while(c<p.size);if(       !(i=p[c]));false;e          lsif"$"==i;s.        push             (s.l
+ast);elsif"%"==i;s.pop;elsif(28.chr)==i;s.push(s.pop,s.p     op);elsif"@"==i;s[        -3],s[-2],s[-1]=s      [-2]           ,s[-
+                  1],s            [-3]               ;els           if"+             "==i            ;s.p     ush(         s.po
+                  p+s.            pop)                ;el           sif"            -"==              i;s.    push       (-s.
+                  pop+            s.po                p);           elsi            f"*"              ==i;    s.pu     sh(s
+                  .pop            *s.p               op);           elsi            f"/"                      ==i;   s.pu
+                  sh(s            .pop.then{s.pop/_1});e            lsif            "_"=                      =i;s.push
+                  (-s.            pop);elsif"&"==i;s.pu             sh(s            .pop                      &s.pop);el
+                  sif"            |"==   i;s.                       push            (s.p                      op|s    .pop)
+                  ;els            if"~     "==i                     ;s.p            ush(              ~s.p    op);       elsi
+                  f">"            ==i;       s.pu                   sh((            s.po              p<s.    pop)         ?~0:
+                  0);e            lsif         "="=                 =i;s             .pus            h((s     .pop           ==s.
+                  pop)            ?~0:           0);elsif"   !"==i;self.false(s        .pop,s,v);elsif"?      "==i             ;s.pop.then{s.pop!=0&
+                  &sel            f.fa             lse(_1,   s,v)};elsif":"==i;          v[s.pop]=s.po        p;el               sif";"==i;s.push(v[
+
+
+s.pop]);elsif","==i;print(s.pop.chr)               ;elsif"."==i;p       rint(s.pop);elsi                f/[0-9]/=~i;s.push(i.to_i);elsif/[a-z]/=~i;s
+.push(i);elsif"["==i;q=c+=(b=1);while(b          !=0);b+={"["=>1,"]     "=>-1}[p[c]]||0;c+=          1;end;s.push(p[q...(c-=1)]);elsif"#"==i;a,b=s.p
+                                    op,s        .pop            ;loo                    p{;s        elf.
+                                    fals       e(b                ,s,                   v);s        .pop
+                                   !=0&        &br                eak                  ;sel          f.fa
+                                 lse(          a,s                ,v)                ;};e              nd;c
+                              +=1;e            nd;                end             ;clas                  s'Str
+                           ing;d               ef&                (ot          her);                        (self
+                         [1..                  ]+o                the        r[1.                              .]).
+                       char                    s.m                ap{      (_1.                                  upca
+                      se==                     _1)                ??1     :?0}                                    .joi
+                      n.to                      _i(2            ).ch      r;en                                    d;de
+                       f|(other);(self||""       )+(other||"");end;        def'method_missing(_);self;end;end;def'Obj
+                          ect.const_missin         g(n);const_set             (n,n.to_s);end}.join.gsub("'"," "))
+
+
+
+
+     EPISODE_VII
+
+  THE_FALSE_AWAKENS
+
+
+
+
+self.false((
+  May.the.false.be.with.you;
+  TrUE&FaLsE|TrUe&FaLse|TrUe&FAlSe|TrUE&FalSE|TrUe&FAlSe|TrUe&FaLse|TrUe&FaLse|TrUe&FaLse|TrUe&FaLse|TrUE&FAlsE|TrUe&FAlSE|TrUe&FALse|
+  TrUE&FaLSE|TrUe&FAlSE|TrUe&FALse|TrUE&FalSe|TrUe&FALsE|TrUe&FALse|TrUE&FAlse|TrUe&FALsE|TrUe&FALse|TrUe&FALse|TrUE&FaLse|TrUE&FAlse|
+  TrUe&FAlSe|TrUe&FALse|TrUE&FaLsE|TrUE&FalSe|TrUE&False|TrUE&FalSe|TrUe&FALSe|TrUe&FALSe|TrUe&FALSe|TrUe&FALSe|TrUE&FalSe|TrUE&FaLsE|
+  TrUe&FAlSe|TrUe&FALse|false
+))
diff --git a/2-the-false-awakens/remarks.markdown b/2-the-false-awakens/remarks.markdown
new file mode 100644
index 0000000..7f072a9
--- /dev/null
+++ b/2-the-false-awakens/remarks.markdown
@@ -0,0 +1,248 @@
+# Episode VII: The False Awakens
+
+> A long time ago in a galaxy far,
+> far away....
+
+
+
+
+## Remarks
+
+Just run it with:
+
+```
+$ ruby entry.rb
+```
+
+It will output "TRICK 2025".
+
+It has been tested under the following environment:
+
+```
+$ ruby --version
+ruby 3.4.1 (2024-12-25 revision 48d4efcb85) +PRISM [x86_64-linux]
+```
+
+
+
+## Description
+
+The program consists of two parts:
+
+* an interpreter of a subset of [FALSE esolang](https://esolangs.org/wiki/FALSE) and
+* an obfuscated FALSE source code.
+
+### FALSE interpreter
+
+The interpreter part is embeeded into an ASCII art, "TRICK 2025" shaped like the Star Wars logo.
+For more readable version, see `entry.clean.rb`.
+
+### FALSE source code
+
+The FALSE source code is encoded to the following expression:
+
+```
+  TrUE&FaLsE|TrUe&FaLse|TrUe&FAlSe|TrUE&FalSE|TrUe&FAlSe|TrUe&FaLse|TrUe&FaLse|TrUe&FaLse|TrUe&FaLse|TrUE&FAlsE|TrUe&FAlSE|TrUe&FALse|
+  TrUE&FaLsE|TrUe&FAlSE|TrUe&FALse|TrUE&FalSe|TrUe&FALsE|TrUe&FALse|TrUE&FAlse|TrUe&FALsE|TrUe&FALse|TrUe&FALse|TrUE&FaLse|TrUE&FAlse|
+  TrUe&FAlSe|TrUe&FALse|TrUE&FaLsE|TrUE&FalSe|TrUE&False|TrUE&FalSe|TrUe&FALSe|TrUe&FALSe|TrUe&FALSe|TrUe&FALSe|TrUE&FalSe|TrUE&FaLsE|
+  TrUe&FAlSe|TrUe&FALse|false
+```
+
+Decoded version:
+
+```
+5$*3*$$$$9+,7+,2-,8-,,48*,5202....25*,
+```
+
+FALSE is a simple stack-based esolang. For instance,
+
+* `5` pushes 5: `[5]`
+* `$` duplicates the top: `[5 5]`
+* `*` pushes the product: `[25]`
+* `3` pushes 3: `[25 3]`
+* `*` pushes the product: `[75]`
+* `$$$$` duplicates the top 4 times: `[75 75 75 75 75]`
+* `9` pushes 9: `[75 75 75 75 75 9]`
+* `+` pushes the sum: `[75 75 75 75 84]`
+* `,` writes the character: `[75 75 75 75]` (output `T`)
+* `7` pushes 9: `[75 75 75 75 7]`
+* `+` pushes the sum: `[75 75 75 82]`
+* `,` writes the character: `[75 75 75]` (output `R`)
+* ...
+
+
+The source code is full of Star Wars references and homages.
+
+
+```
+# A long time ago in a galaxy far,
+# far away....
+```
+
+This is the iconic Star Wars opening phrase.
+
+```
+# (inside the eval'ed code)
+
+  while(c<p.size);
+    if(!(i=p[c]));false;
+    elsif"$"==i;s.push(s.last);
+    elsif"%"==i;s.pop;
+    ...
+```
+
+All comparison operations used in the program are written in the so-called "Yoda notation" (placing constants on the left hand side), referencing the Jedi Master Yoda.
+
+
+```
+     EPISODE_VII
+
+  THE_FALSE_AWAKENS
+```
+
+This parodies the Star Wars Episode VII subtitle, "The Force Awakens."
+"Force" refers to a supernatural power in Star Wars, but for our program, "false" has awakened instead because we used many `false`s.
+
+
+```
+  May.the.false.be.with.you;
+```
+
+This is a twist on one of the most famous Star Wars lines, "May the Force be with you."
+
+
+
+
+## Internals
+
+### FALSE interpreter
+
+The interepreter is implemented as a method named `false`. In Ruby, you can use keywords as method names like this. It cannot be invoked directly, but you can call such a method via explicit receiver:`self.false()`
+
+
+### Encoding the FALSE program
+
+The FALSE program is obfuscated like this:
+
+```
+  TrUE&FaLsE|TrUe&FaLse|TrUe&FAlSe|TrUE&FalSE|TrUe&FAlSe|TrUe&FaLse|TrUe&FaLse|TrUe&FaLse|TrUe&FaLse|TrUE&FAlsE|TrUe&FAlSE|TrUe&FALse|
+  TrUE&FaLsE|TrUe&FAlSE|TrUe&FALse|TrUE&FalSe|TrUe&FALsE|TrUe&FALse|TrUE&FAlse|TrUe&FALsE|TrUe&FALse|TrUe&FALse|TrUE&FaLse|TrUE&FAlse|
+  TrUe&FAlSe|TrUe&FALse|TrUE&FaLsE|TrUE&FalSe|TrUE&False|TrUE&FalSe|TrUe&FALSe|TrUe&FALSe|TrUe&FALSe|TrUe&FALSe|TrUE&FalSe|TrUE&FaLsE|
+  TrUe&FAlSe|TrUe&FALse|false
+```
+
+Each segment separated by `|` represents one instruction.
+
+* `TrUE&FaLsE` => `5`
+* `TrUe&FaLse` => `$`
+* `TrUe&FAlSe` => `*`
+* ...
+
+This is achieved by defining `Object.const_missing`, `String#&`, and `String#|`.
+
+First, our `const_missing `dynamically defines constants like `TrUE`:
+
+```
+# (inside the eval'ed code)
+
+def Object.const_missing(n);
+  const_set(n,n.to_s);
+end;
+```
+
+With that, constant `TrUE` is resolved to string `"TrUE"`.
+
+Second, such strings are concatenated with `&` with special decoding:
+
+```
+# (inside the eval'ed code)
+
+class'String;
+  def&(other);
+    (self[1..]+other[1..])
+      .chars
+      .map{(_1.upcase==_1)??1:?0}
+      .join
+      .to_i(2)
+      .chr;
+  end;
+end;
+```
+
+For `TrUE & FaLsE`,
+
+```
+    (self[1..]+other[1..])              # => "rUEaLsE"
+      .chars                            # => ["r","U","E","a","L","s","E"]
+      .map{(_1.upcase==_1)??1:?0}       # => ["0","1","1","0","1","0","1"]
+      .join                             # => "0110101"
+      .to_i(2)                          # => 53
+      .chr;                             # => "5"
+```
+
+Finally, each FALSE instruction is concatenated by `|` operator:
+
+```
+# (inside the eval'ed code)
+
+class'String;
+  def|(other);
+    (self||"")+(other||"");
+  end;
+end;
+```
+
+
+# Misc.
+
+```
+     EPISODE_VII
+
+  THE_FALSE_AWAKENS
+```
+
+This code is equivalent to this:
+
+```
+     "EPISODE_VII"
+
+  "THE_FALSE_AWAKENS"
+```
+
+It does nothing.
+
+```
+  May.the.false.be.with.you;
+```
+
+`May` is resolved to string `"May"` and the rest method chain is dispatched to `String#method_missing` defined here:
+
+```
+# (inside the eval'ed code)
+
+class'String;
+  def'method_missing(_);
+    self;
+  end;
+end;
+```
+
+It does nothing too.
+
+
+
+
+
+## Limitations
+
+Our FALSE interpreter does not support the following instructions:
+
+* `'c`: literal character "c"
+* `ø`: pick
+* `^`: input
+* `"string"`: output "string"
+* `ß`: flush the inout/output buffer.
+* `{...}`: comments
+* `\``: compile
+
+Also, only one-digit numeric literals are supported, so `123` is interpreted as pushing `1`, `2` and `3` separately.
diff --git a/3-ruby-tags/Gemfile b/3-ruby-tags/Gemfile
new file mode 100644
index 0000000..72dcf70
--- /dev/null
+++ b/3-ruby-tags/Gemfile
@@ -0,0 +1,5 @@
+# frozen_string_literal: true
+
+source "https://rubygems.org"
+
+gem "webrick"
diff --git a/3-ruby-tags/Gemfile.lock b/3-ruby-tags/Gemfile.lock
new file mode 100644
index 0000000..b0d2268
--- /dev/null
+++ b/3-ruby-tags/Gemfile.lock
@@ -0,0 +1,14 @@
+GEM
+  remote: https://rubygems.org/
+  specs:
+    webrick (1.9.1)
+
+PLATFORMS
+  ruby
+  x86_64-linux
+
+DEPENDENCIES
+  webrick
+
+BUNDLED WITH
+   2.6.2
diff --git a/3-ruby-tags/authors.markdown b/3-ruby-tags/authors.markdown
new file mode 100644
index 0000000..f308e56
--- /dev/null
+++ b/3-ruby-tags/authors.markdown
@@ -0,0 +1,3 @@
+* Kensuke Imamura (@nsfisis)
+    * nsfisis@gmail.com
+    * cctld: jp
diff --git a/3-ruby-tags/entry.rb b/3-ruby-tags/entry.rb
new file mode 100644
index 0000000..4ad7b7f
--- /dev/null
+++ b/3-ruby-tags/entry.rb
@@ -0,0 +1,120 @@
+eval $s=<<'TRICK'
+require "cgi"
+require "js"
+require "prism"
+
+@s = String.new
+def p(s) = @s << s
+
+def tag(t, s, c) = "<#{t} class=#{c}>#{s}</#{t}>"
+def span(s, c) = tag("span", s, c)
+
+def ruby(t)
+  s = CGI.escape_html(t.value)
+  if r = rt(t)
+    tag("ruby", s + tag("rp", "(", "") + tag("rt", r, "") + tag("rp", ")", ""), t.type)
+  else
+    span(s, t.type)
+  end
+end
+
+def kana(s)
+  s
+    &.scan(/.{2}/)
+    &.map{|c| (0x30A0 + c.to_i).chr(Encoding::UTF_8)}
+    &.*("")
+end
+
+def rt(t)
+  r = {
+    :"&&" => "1136",
+    :"=" => "04199275",
+    :"||" => "623147",
+    :$s => "41750825",
+    :* => "111775",
+    :+ => "557325",
+    :- => "62044225",
+    :<< => "02588341",
+    :@s => "0235400825",
+    LESS: "2371064274",
+    USTAR: "",
+    c: "2392",
+    cgi: "239224920204",
+    chr: "336792",
+    def: "3953",
+    document: "411369658340",
+    downcase: "320683179225",
+    each: "043533",
+    else: "087525",
+    encoding: "0883199239038316",
+    end: "088341",
+    end_column: "088341117364",
+    end_line: "088341730483",
+    end_with?: "088341060326",
+    escape_html: "082517925508043338039208640875",
+    getelementbyid: "183540087665834048040204390392",
+    global: "1677924875",
+    if: "0453",
+    innerhtml: "0483429208043338039208640875",
+    js: "2407920825",
+    kana: "1142",
+    l: "0875",
+    lex: "76351525",
+    location: "771792237183",
+    map: "623555",
+    new: "436992",
+    nil: "4375",
+    p: "5292",
+    prism: "55742664",
+    r: "029275",
+    require: "7415790402",
+    rp: "0292755292",
+    rt: "029275380392",
+    ruby: "7551",
+    s: "0825",
+    scan: "25136783",
+    span: "254983",
+    star: "111775",
+    start_column: "25319240117364",
+    start_line: "25319240730483",
+    string: "2540748316",
+    t: "380392",
+    tag: "3116",
+    to_i: "4005920204",
+    type: "310455",
+    utf_8: "70923803920853080440",
+    value: "48746992",
+    x: "08351525",
+    y: "7904",
+  }
+  kana(
+    r[:"#{t.type}"] ||
+    r[s = :"#{t.value.downcase}"] ||
+    s.end_with?(":") && r[:"#{s[..-2]}"] ||
+    nil
+  )
+end
+
+y = 1
+x = 0
+Prism.lex($s).value[..-2].each {|t, *|
+  l = t.location
+  r = l.start_line
+  if y < r
+    p "\n" * (r - y)
+    x = 0
+  end
+  c = l.start_column
+  if x < c
+    p " " * (c - x)
+  end
+  p ruby(t)
+  y = l.end_line
+  x = l.end_column
+}
+
+JS.global[:document].getElementById("src")[:innerHTML] =
+  span("eval $s=<<'TRICK'\n", "COMMENT") +
+  @s +
+  span("TRICK\n", "COMMENT")
+TRICK
diff --git a/3-ruby-tags/index.html b/3-ruby-tags/index.html
new file mode 100644
index 0000000..63a6a6d
--- /dev/null
+++ b/3-ruby-tags/index.html
@@ -0,0 +1,45 @@
+<html>
+  <script src="https://cdn.jsdelivr.net/npm/@ruby/3.4-wasm-wasi@2.7.1/dist/browser.script.iife.js"></script>
+  <script type="text/ruby" src="entry.rb"></script>
+  <title>TRICK 2025 (Episode I)</title>
+  <body>
+    <style>
+      pre {
+        background-color: #eee;
+        color: #333;
+        padding: 1em;
+        border-radius: 4px;
+        overflow: auto;
+      }
+
+      .COMMENT {
+        color: #777;
+        font-style: italic;
+      }
+
+      .CONSTANT, .GLOBAL_VARIABLE, .INSTANCE_VARIABLE, .IDENTIFIER {
+        color: #088;
+      }
+
+      .KEYWORD_BREAK, .KEYWORD_CASE, .KEYWORD_DEF, .KEYWORD_ELSE, .KEYWORD_END, .KEYWORD_IF, .KEYWORD_IF_MODIFIER, .KEYWORD_WHEN {
+        color: #04c;
+        font-weight: bold;
+      }
+
+      .INTEGER, .KEYWORD_NIL {
+        color: #990;
+      }
+
+      .STRING_BEGIN, .STRING_END, .HEREDOC_START, .HEREDOC_END, .REGEXP_BEGIN, .REGEXP_END, .SYMBOL_BEGIN, .LABEL, .STRING_CONTENT {
+        color: #d50;
+      }
+
+      ruby * {
+        user-select: none;
+      }
+    </style>
+    <main>
+      <pre style="font-size: 16px;"><code id="src"></code></pre>
+    </main>
+  </body>
+</html>
diff --git a/3-ruby-tags/remarks.markdown b/3-ruby-tags/remarks.markdown
new file mode 100644
index 0000000..2621a32
--- /dev/null
+++ b/3-ruby-tags/remarks.markdown
@@ -0,0 +1,63 @@
+# Ruby Tags
+
+
+
+## Remarks
+
+This program utilizes `ruby.wasm`. To run it, first launch an HTTP server:
+
+```
+$ bundle install
+$ bundle exec ruby -run -e httpd
+```
+
+Then access <http://127.0.0.1:8080/>.
+
+NOTE: gems are used only for the server.
+
+It has been tested under the following environment:
+
+```
+$ ruby --version
+ruby 3.4.1 (2024-12-25 revision 48d4efcb85) +PRISM [x86_64-linux]
+```
+
+`ruby.wasm` version:
+
+```
+<script src="https://cdn.jsdelivr.net/npm/@ruby/3.4-wasm-wasi@2.7.1/dist/browser.script.iife.js"></script>
+```
+
+
+
+## Description
+
+This is a quine-like program that renders its own source code as HTML elements in browser.
+In addition, it highlights the source code and adds "ruby" annotations for each token.
+
+Example for `<ruby>` tag: https://developer.mozilla.org/en-US/docs/Web/HTML/Element/ruby
+
+> ```
+> <ruby> 明日 <rp>(</rp><rt>Ashita</rt><rp>)</rp> </ruby>
+> ```
+
+The pronounciation table is compressed and hard-coded to `entry.rb`.
+
+
+
+## Internals
+
+### Syntax Highlighting
+
+Syntax highlighting is powered by Prism, a recently introduced parser/lexer ecosystem. The program calls `Prism.lex()` and iterates over the resulting token stream to apply highlighting.
+
+### Ruby Annotations
+
+Initially, I tried adding ruby annotations to *every* token. However, the pronounciation data for all tokens was too large to fit within the size limit. Although I implemented a simple compression algorithm (see `kana()` function), I finally had to reduce the table size.
+
+### Compression Algorithm for the Pronounciation Table
+
+The compression algorithm is fairly simple: each Katakana letter is encoded as a two-digit integer, offset by U+30A0.
+There are certainly more sophisticated approaches.
+
+Because the `index.html` has no strict size limit according to the regulation, the table data could be embedded there instead. However, that approach was not very elegant.
diff --git a/README.md b/README.md
new file mode 100644
index 0000000..669021c
--- /dev/null
+++ b/README.md
@@ -0,0 +1,7 @@
+# My entries of TRICK 2025
+
+I submitted the following entries to TRICK 2025:
+
+* [3x3 Sliding Puzzle Quine](./1-sliding-puzzle/)
+* [Episode VII: The False Awakens](./2-the-false-awakens/)
+* [Ruby Tags](./3-ruby-tags/)