Re: [Fwd: LOGO-L> ideas needed!!!]

[Michael Tempel <michaelt@media.mit.edu>]

This list has seen some pretty severe turtle bashing of late.  Mike Doyle says:

>Turtle Geometry relates a procedure in TPN to a *static* drawing on the
>screen. The screen is used exactly as the paper upon which the floor
>turtle draws. Thus, Turtle Geometry is *fundamentally* a pencil-and-paper
>geometry. The only process represented is that of drawing.

The difference is that the turtle does exactly what you tell it to do.
This may or may not be what you thought you told it to do.  Very often it
isn't.  This leads to a  process of debugging.  You just can't do that with
pencil and paper.

(It's an interesting idea that  changing the drawing should revise the
procedure that drew it.  In addition to Geomland, which I don't know,
Turtle Math, developed by Doug Clements and Julie Samara Meredith, has this
feature.  I'm not sure if this is good or not.  Does this help or hinder
the debugging process?)

It's also not  true that Turtle Geometry is only about drawing.  The
epistemological basis of Turtle Geometry is that it is "body syntonic".  It
moves the way you and I do.  This makes it possible for the learner to have
a direct, personal, geometric experience.  The robot turtles don't just
draw.  They sense their environment and react.  They move through mazes and
knock things over. There is mathematical, geometric content to the
instructions we give them to make them do this, but this isn't about
drawing.

There's also a rich body of work with "sprites" - turtles that act like
spaceships, birds, and clouds. They don't draw. They're certainly not
"static".

The turtle is not merely "emulating formal pencil-and-paper techniques" as
Mike Doyle claims.

I do agree with Mike in one respect.  He says:

>Logo and Turtle Geometry are separate entities. Turtle Procedure
>Notation may be implemented in any computer language. [snip] Logo is much,
>>much, much, much more than this.

Yes. Turtle geometry is only one of many Logo domains, and there are turtle
systems that do not use Logo, for example, Roamer.  This robot turtle has a
very limited instruction set.  It's good for starters, but in order to
build up complexity you need Logo.  But this in no way invalidates Logo or
Turtle Geometry.

-Michael

P.S. A discussion of some issues around these themes appeared in Logo
Update, Vol. 4  No 1, Fall 1995, with articles by Jose Valente, myself, and
Dorothy Fitch and David McLees.  You can get a copy from our Web site at

http://el.www.media.mit.edu/groups/logo-foundation/LU/v4n1.html

or I can send it to you via snail mail.


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