Self-reproducing Spiral

Tyler F. Creelan creelan at engr.orst.edu
Mon Jul 15 21:43:02 CDT 2002


Can anyone explain how this (very awesome!) perl code works?

"This self-reproducing code prints a turning spiral filled with it's own
code."

#!/usr/bin/perl
$_='
         $q ="\                   47"; wh
        ile                           ($ ;=
      $z                +=              .5 ){
    %c=           $r=0;$/ ="";whi         le(2
   0+          $z>($;+=.05)){$c{int$       _+ 2
  6+         2*($              r+= .0       2) *
 s          in$                   ;}{1       -$_
+1         0+           int        $r*c       o s
$         ;}         =1for(0.       .1)        }$
t        =r         ever se;$        /.        =`
c        le        ar     `.         "         #!
/        usr       /bi             n/         pe
rl       \n\       $_ =$q        \n"          ;
fo        r$y        (1..20){$c{$_}          {
$ y       }? $         /.=chop$t            :
 ($/        . ="                          \4
 0")         for(0.                    .53)          ;
   $/.        ="\n"}pri            nt"$/$          q;
   s; ".         chr(9 2)."s;;g;eval\n           "}

';s;\s;;g;eval


Source: http://www.perlmonks.org/index.pl?node_id=176043

Also a Win32 version:


#!/usr/bin/perl
$_='
         $q ="\                   47"; wh
        ile                           ($ ;=
      $z                +=              .5 ){
    %c=           $r=0;$/ ="";whi         le(2
   0+          $z>($;+=.05)){$c{int$       _+ 2
  6+         2*($              r+= .0       2) *
 s          in$                   ;}{1       -$_
+1         0+           int        $r*c       o s
$         ;}         =1for(0.       .1)        }$
t        =r         ever se;$        /.        =`
c        le        ar     `.         "         #!
/        usr       /bi             n/         pe
rl       \n\       $_ =$q        \n"          ;
fo        r$y        (1..20){$c{$_}          {
$ y       }? $         /.=chop$t            :
 ($/        . ="                          \4
 0")         for(0.                    .53)          ;
   $/.        ="\n"}pri            nt"$/$          q;
   s; ".         chr(9 2)."s;;g;eval\n           "}

';s;\s;;g;eval


TIMTOWTDI



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