From: dal3@cbnewsg.cb.att.com (dale.e.parson)
Subject: Re: Beginning Logo lesson plans/project ideas?
Organization: AT&T
Date: Wed, 9 Sep 1992 17:21:04 GMT

In article <18l195INNqvs@agate.berkeley.edu> bh@anarres.CS.Berkeley.EDU (Brian Harvey) writes:
>
>If you're interested in geometric constructions that aren't square-triangle-
>house you might look for the book
>
>	Visual Modeling with Logo
>	James Clayson, MIT Press, 1988
>
>It's not written for young kids -- Clayson teaches a college course from it --
>but it's full of good ideas that a parent or teacher could use as starting
>points for work you do with your kid(s).

I heartily second the recommendation for this book. It's a gold mine that
I've used for ideas for working with both middle school and elementary school
age kids (the latter my own). The author is an artist, at I've winced
once or twice over some science/math nasties--e.g., one college student
wanting to draw lunar phases goes on about lunar phases being caused by
the Earth's shadow on the moon, when in fact only lunar eclipses are caused
that way, if he were to go out & actually LOOK at a setting sun & a closely
following, waxing crescent moon he'd see where the shadow comes from--
but the book has such good visual ideas that I won't complain.

Following up on the earlier post about the boredom of drawing
rectangle/triangle houses, etc., another variation that's interesting
is replacing 'fd' with more elaborate variations that get the turtle
from where it's at to where 'fd' would send it, but by following a more
circuitous route. You can use such procedures anywhere you'd use fd.
You can segue into fractals using this. For example, change a triangle

to tri :length
repeat 3 [fd :length rt 120]
end

into a Koch curve (snowflake)

to snow :distance :limit
repeat 3 [snowside :distance :limit rt 120]
end

Where 'snowside' has replaced 'fd'. In this example 'snowside' is not an
exact replacement for 'fd', since it takes both distance & limit parameters.
Parameters for the 'fd' substitutes will depend on how you want to mutate
the 'fd' notion. Here's snowside:

to snowside :distance :limit
if or lessp :distance :limit equalp :distance :limit [fd :distance stop]
snowside :distance / 3 :limit
lt 60
snowside :distance / 3 :limit
rt 120
snowside :distance / 3 :limit
lt 60
snowside :distance / 3 :limit
end

You have to know a little about equilateral triangles for this to
make sense. The fd-substitutes have to make exact turtle trips--
here the lt's & rt's cancel out. If such an fd-substitute is too
advanced for the kids you're working with, they are sure to find others
that aren't. There are many interesting ways to get a turtle from
here to there.

Dale Parson, Bell Labs, dale@mhcnet.att.com

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|    "These words are too solid, they don't move fast enough           |
|     to catch the blur in the brain that flies by, and is gone..."    |
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|     Suzanne Vega                                                     |
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