Variables have always been in etoys.

Etoys documentation can be found on squeakland.org.

Cheers,

Alan
-------------
At 01:03 AM 12/24/2004, hjh-sqlist at lexdb.net wrote:
>Hi
>
>The Newtonian orbits screen is impressive. I'd like to learn how that is done.
>I see that now variables are possible in eToys. The last time I looked into
>eToys (some time ago..) this wasn't possible.  Is there a tutorial or a short
>movie which shows how to use them? How do I define them?
>
>On http://www.squeakland.org/author/etoys.html in particular (e.g. quickstart
>guide) I do not see anything like that.
>
>Hannes
>
>
>Quoting Alan Kay <alan.kay at squeakland.org>:
>
> > It is also very easy to do Newtonian orbits in etoys, if full precision is
> > used for acc, vel, and position properties. The script looks just as one
> > would like: do this in a playfield with origin at center, place the sun
> > there, and the vector distance of the earth is also its distance to the
> > sun. It's not science to claim inverse square, but it's one of the
> > plausible hypotheses with an analogy to the intensity of light. Newton
> > actually proved his stuff as math long before he got to the last books
> > where he looked to see how the phenomena in the world behaved. Given this
> > as an hypothesis, the script is straightforward: the strength of the force
> > being inversely proportional to the square of the distance, and the
> > direction of the accelleration is the opposite direction of the vector 
> that
> > is the Earth.
> >
> > Cheers,
> >
> > Alan
> >