The one they invented to justify hating coding standards.

The human might use a carefully selected mix of tabs and spaces to output a picture. And formatter will destroy it, thus destroying artist expression.

Compare:

    #define/**/Q(x,y)r;char*q/*                         */=y#x","#y")",*p,x=*p%67;}
      /*-IOCCC2020-*/#include/*                         */<stdio.h>/*-BBQlock--*/
        int(y),x,i,k,Q(s[9<<9/*           12            */];float(f)[3];void(Z)
          (){*f=r<0?r:-r;f[1]/*      11         1       */=42.5;f[2]=22.5;for
           (k=0;++k<39;*f/=(k/*   10               2    */%2?k:-k)*6875.5/i)
            y=f[1+k%2]+=*f;k=/*                         */f[2];p=s+k/2*86+y
             ;}int(main)(){p=/*  9         o-------> 3  */s;for(;i<1978;*q
              >32?k=i++/86-11/*           /             */,y=(750>r*r+k*k
              *4)*4+y/2,*p++=/*    8     L         4    */r<44?y?"+0X+0X"
               "+!"[y]-1:*q++/*       7         5       */:10:*q++)r=-41
               +i%86;r=20;for/*            6            */(x=13;(i=3600*
               --x);*p++="XR"/*                         */"MOQSUWAY"[x%+
               10]-9,*p+=x/10/*                         */*41)Z();sscanf
               (__TIME__,"%d"/*  \       /    -------+  */":%d:%d",&k,&x
              ,&i);r=10;for(i/*   \     /     ------ |  */+=(k*60+x)*60;r
              +18;*p=k%2?*p%2/*    \   /      ------ |  */?59:44:*p>39?59
             :39,i=r--?i:i%(+/*     \ /       ------ |  */3600)*12)Z();for
            (p=s;*p;putchar(k/*      X        ------ |  */%2&&k<14?q="End",
           printf("%c%c",224|/*   __/ \__         |  |  */(21554>>k&3),"gCS"
          "gGMX"[k/2]+65),"E"/*  /  \ /  \        |  |  */"Gh_BrG"[k/2]+64:*p
        ),++p)k,"#define/**/"/*  \__/ \__/        +--+  */"Q(x,y)r;cha""r*q=y#"
      "x\",\"#y\")\",*p,x=*p"/*                         */"%67;}/*-IOCCC2020-*/#"
    "include<stdio.h>/*-BBQl"/*                         */"ock--*/int(y),x,i,k,Q(")

    #define /**/ Q(x, y)                                                           \
      r;                                                                           \
      char *q /*                         */ = y #x "," #y ")", *p, x = *p % 67;    \
      }
    /*-IOCCC2020-*/ #include /*                         */<stdio.h> /*-BBQlock--*/
            int(y),x,i,k,Q(s[9<<9/*           12            */];float(f)[3];void(Z)
              (){
      *f = r < 0 ? r : -r;
      f[1] /*      11         1       */ = 42.5;
      f[2] = 22.5;
      for (k = 0; ++k < 39;
           *f /= (k /*   10               2    */ % 2 ? k : -k) * 6875.5 / i)
        y = f[1 + k % 2] += *f;
      k = /*                         */ f[2];
      p = s + k / 2 * 86 + y;}int(main)(){
      p = /*  9         o-------> 3  */ s;
      for (; i < 1978; *q > 32 ? k = i++ / 86 - 11 /*           /             */,
                                 y = (750 > r * r + k * k * 4) * 4 + y / 2,
                                 *p++ = /*    8     L         4    */ r < 44
                                            ? y ? "+0X+0X"
                                                  "+!"[y] -
                                                      1
                                                : *q++ /*       7         5       */
                                            : 10
                               : *q++)
        r = -41 + i % 86;
      r = 20;for/*            6            */(x=13;(i=3600*
                   --x);*p++="XR"/*                         */"MOQSUWAY"[x%+
                   10]-9,*p+=x/10/*                         */*41)
        Z();
      sscanf(__TIME__, "%d" /*  \       /    -------+  */ ":%d:%d", &k, &x, &i);
      r = 10;
      for (i /*   \     /     ------ |  */ += (k * 60 + x) * 60; r + 18;
           *p = k % 2     ? *p % 2 /*    \   /      ------ |  */ ? 59 : 44
                : *p > 39 ? 59
                          : 39,
           i = r-- ? i : i % (+/*     \ /       ------ |  */ 3600) * 12)
        Z();
      for (p = s; *p;
           putchar(k /*      X        ------ |  */ % 2 &&k < 14
                   ? q = "End",
                     printf("%c%c",
                            224 | /*   __/ \__         |  |  */ (21554 >> k & 3),
                            "gCS"
                            "gGMX"[k / 2] +
                                65),
                     "E" /*  /  \ /  \        |  |  */ "Gh_BrG"[k / 2] + 64 : *p),
          ++p)k,"#define/**/"/*  \__/ \__/        +--+  */"Q(x,y)r;cha""r*q=y#"
          "x\",\"#y\")\",*p,x=*p"/*                         */"%67;}/*-IOCCC2020-*/#"
        "include<stdio.h>/*-BBQl"/*                         */"ock--*/int(y),x,i,k,Q(")