anchor.diff:  matrix->vov,procedure,2,http://www.cs.indiana.edu/cgi-pub/c211/wombat/docs/c211-matrix.htm#matrix->vov
   vov->matrix,procedure,2,http://www.cs.indiana.edu/cgi-pub/c211/wombat/docs/c211-matrix.htm#vov->matrix
   
  -; c211 tree library
  +; c211 tree librar
  +; matrix,library,2,http://www.cs.indiana.edu/cgi-pub/c211/wombat/docs/c211-matrix.htm ; already a procedure
   draw-tree,procedure,2,http://www.cs.indiana.edu/cgi-pub/c211/wombat/docs/c211-tree.htm#draw-tree
   empty-tree,procedure,2,http://www.cs.indiana.edu/cgi-pub/c211/wombat/docs/c211-tree.htm#empty-tree
   empty-tree?,procedure,2,http://www.cs.indiana.edu/cgi-pub/c211/wombat/docs/c211-tree.htm#empty-tree?
  
positive.code: yellow,procedure,2,
  
  ; c211 matrix library
  draw-matrix,procedure,2,http://www.cs.indiana.edu/cgi-pub/c211/wombat/docs/c211-matrix.htm#draw-matrix
  make-matrix,procedure,2,http://www.cs.indiana.edu/cgi-pub/c211/wombat/docs/c211-matrix.htm#make-matrix
  matrix-cols,procedure,2,http://www.cs.indiana.edu/cgi-pub/c211/wombat/docs/c211-matrix.htm#matrix-cols
  
negative.code: ; c211 image library
  image,library,2,http://www.cs.indiana.edu/cgi-pub/c211/wombat/docs/c211-image.htm
  black,procedure,2,
  blue,procedure,2,
  color,procedure,2,http://www.cs.indiana.edu/cgi-pub/c211/wombat/docs/c211-image.htm#color
  