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 PNG

\x89\x50\x4E\x47\x0D\x0A\x1A\x0A
/* Construct subgraph reachable from node ARGV[0] by forward edges */
BEG_G {
  node_t r = node($,ARGV[0]);

  $tvroot = r;
  $tvtype = TV_fwd;
}
N{$tvroot=NULL; subnode($T,$);}