[Edu-sig] turtle coordinates: Y increase downards - as in most graphics API?

[Sergio Rojas]

> From: Kevin Cole <kevin.cole at novawebdevelopment.org>

> In spite of the common "in computer graphics Y goes down", does that make
> sense to new learners? I've gotten used to various coordinate systems, but
> the first time I had to work with graph paper and plotting (and, for that
> matter, maps) one goes "up" ("north", "forward") for Y. 
...
...

> From: kirby urner <kirby.urner at gmail.com>

> This arrangement of two numbered lines considered "most normal" i.e. this
> schema is rather ubiquitous and must be considered something of a home base
> in classroom projects.
...

> However if you walk around to the back and look from the other side... my
> right is your left and so on -- these are terms relative to a point of
> view, not to the object in front of us, which is where the confusion often
> begins. Who's left?

> Stage left means what again? It's the actor's left, not the audience's
> left. 
...
> Math texts don't believe in talking about an observer for some reason, or
> multiple observers. I expect the influence of computer science to be a
> positive influence in helping address that blind spot over time.

Perhaps teachers of physics could be called to make appreciations in
their courses about the relativeness (in most cases) on chosen a coordinate 
system: right or left-handed or whatever helps to make computations 
simple (but not simpler).

Some issues to keep in mind:

>From the The Feynman Lectures on Physics: 
   
    http://www.feynmanlectures.caltech.edu/I_52.html
"""
Fig. 52–1(b)! The first molecule, the one that comes from the living 
thing, is called L-alanine. The other one, which is the same chemically, 
in that it has the same kinds of atoms and the same connections of the 
atoms, is a “right-hand” molecule, compared with the “left-hand” 
L-alanine, and it is called D-alanine. 
...
...
So it looks as though the phenomena of life permit a distinction between 
"right" and "left," ...
"""

Other Related links:
   https://phys.org/news/2014-10-handedness-life.html
   http://www.iflscience.com/space/why-life-left-handed-answer-stars/

Sergio
Check out the free first draft of the book:
     Prealgebra via Python Programming 
     https://www.researchgate.net/publication/325473565
     https://github.com/rojassergio/Prealgebra-via-Python-Programming