http://www.frank-buss.de/lisp/functional.html
http://www.frank-buss.de/lisp/fishes.pdf

See also AIM-986.pdf or the corresponding article of Byte 1988, February.

ftp://publications.ai.mit.edu/ai-publications/pdf/AIM-986.pdf

and

For people who want to see Henderson's ideas in action
this video set is a good choice. I guess it is the 4th or 5th
.avi file that includes a lecture about how to produce
Escher style pictures using a functional programming
language and Henderson's ideas:

 http://swiss.csail.mit.edu/classes/6.001/abelson-sussman-lectures/

Now that we have Common Lisp version which produces
Postscript output, we're one step closer to total world
domination! ;-)

--
Emre Sevinc

"Emre Sevinc" <em...@bilgi.edu.tr> wrote

See:

http://www.lispworks.com/documentation/lw44/CLIM/html/climguide-341.h...

"Rainer Joswig" <jos...@lisp.de> wrote

...about halfway through that video.

Another good part: at the end of the lecture he compares the top-down
methodology with the "levels of languages" methodology and explains why
it is more robust to use embedded languages in Lisp.

Regarding the picture: Would be nice to enhance the program to produce a
more exact reproduction of the original picture, filled with color, with
curved lines and recursive to level n (see "Square Limit"):

http://www.dartmouth.edu/~matc/math5.pattern/lesson7math.html

The second papers discussion of there actually being a single curved
line segment that generates the outline of the fish is the more
interesting piece (IMO).  That curve is drawn about a right triangle,
with some simple operations occurring, but the key rot45 appears on
the hypotenuse.  Following up this concept with a line generator which
is then mapped onto the right triangle for the tessellations, in
common lisp with .ps (or .pdf) output would be neat.

Thanks for providing some interesting reading and thinking Frank!

(loop for line in s collect
      (mapcar (lambda (point)
                (p+ (p/ (p* b (first point)) m) a (p/ (p* c (second point)) n)))
              line))

and alter PLOT:

(ecase (length line)
    (2  (... "~D ~D moveto ~D ~D lineto~%" ...))
    (4  (... "~D ~D moveto ~D ~D ~D ~D ~D ~D curveto~%" ...)))

That should do it. (untested)

http://lispm.dyndns.org/lisp/pics/fg.jpg

Note that you can have commands to manipulate pictures
(via command line, menus or even drag&drop) and
that CLIM can generate postscript.

The code looks like this:

(define-presentation-type picture ())

(define-presentation-method presentation-typep (object (type picture))
  (typep object 'function))

;;; Plotting

(defun clim-plot (p  &optional (stream *standard-output*))
  (fresh-line stream)
  (with-output-as-presentation (stream p 'picture :single-box t)
    (with-room-for-graphics (stream)
      (with-scaling (stream 200 200)
        (with-translation (stream 0.1 0.1)
          (loop for (x0 y0 x1 y1) in '((0 0 1 0) (1 0 1 1) (1 1 0 1) (0 1 0 0))
                do (draw-line* stream x0 y0 x1 y1))
          (dolist (line (funcall p (make-point 0 0) (make-point 1 0) (make-point 0 1)))
            (destructuring-bind (p0 p1) line
              (draw-line stream p0 p1))))))))

(defun clim-plot-in-window (p &optional (stream *standard-output*))
  (clim-plot p stream))

(defun clim-plot-to-postscript (p &optional (pathname "/Users/joswig/Desktop/test-clim.ps"))
  (with-open-file (file-stream pathname
                               :direction :output
                               :if-exists :supersede
                               :if-does-not-exist :create)
   (with-output-to-postscript-stream (stream file-stream)
     (clim-plot p stream))))

(clim-demo::define-lisp-listener-command (clim-demo::save-picture-as-postscript :name t)
    ((picture 'picture :provide-default nil :prompt "picture")
     (file 'pathname :provide-default nil :prompt "file"))
  (clim-plot-to-postscript picture file)
  (values file picture))

(clim-demo::define-lisp-listener-command (clim-demo::com-beside :name t)
    ((picture0 'picture :provide-default nil :prompt "picture 0")
     (picture1 'picture :provide-default nil :prompt "picture 1"))
  (let ((new-picture (beside picture0 picture1)))
    (clim-plot new-picture)
    new-picture))

(clim-demo::define-lisp-listener-command (clim-demo::com-above :name t)
    ((picture0 'picture :provide-default nil :prompt "picture 0")
     (picture1 'picture :provide-default nil :prompt "picture 1"))
  (let ((new-picture (above picture0 picture1)))
    (clim-plot new-picture)
    new-picture))

(clim-demo::define-lisp-listener-command (clim-demo::com-rot :name t)
    ((picture 'picture :provide-default nil :prompt "picture"))
  (let ((new-picture (rot picture)))
    (clim-plot new-picture)
    new-picture))

(clim-demo::define-lisp-listener-command (clim-demo::com-cycle :name t)
    ((picture 'picture :provide-default nil :prompt "picture"))
  (let ((new-picture (cycle picture)))
    (clim-plot new-picture)
    new-picture))

(clim-demo::define-lisp-listener-command (clim-demo::com-quartet :name t)
    ((picture0 'picture :provide-default nil :prompt "picture 0")
     (picture1 'picture :provide-default nil :prompt "picture 1")
     (picture2 'picture :provide-default nil :prompt "picture 2")
     (picture3 'picture :provide-default nil :prompt "picture 3"))
  (let ((new-picture (quartet picture0 picture1 picture2 picture3)))
    (clim-plot new-picture)
    new-picture))

(define-presentation-to-command-translator rot
    (picture clim-demo::com-rot clim-demo::lisp-listener :menu t :gesture :menu)
    (object)
  (list object))

(define-presentation-to-command-translator cycle
    (picture clim-demo::com-cycle clim-demo::lisp-listener :menu t :gesture :menu)
    (object)
  (list object))