[Squeakland] Etoys beginner questions

[Luke Gorrie]

Howdy!

I've recently arrived in Kathmandu to help some people
(http://nepal.ole.org/) with a project to introduce computers into
public schools in Nepal in cooperation with the government. The first
job is to computerise some maths exercises from a textbook and we're
looking at Etoys as a practical (and perhaps subversive) way to
implement this. I'm writing to say hello and see if anyone has tips to
share. I hope this initial project isn't too unrevolutionary for the
list :-)

The main thing that I'm wondering is whether someone has already built
Etoys like the ones we have in mind: "Connect the dots to make the
picture", "How many are two apples and three oranges", "What's the
next shape in the sequence: ABCAB", or something else to drill these
basic concepts (counting, summing small numbers, etc).

I'm a beginner with Etoys but I've found it pretty easy to make a
couple of simple prototypes (based on a recent XO image) which I've
posted here: http://fresh.homeunix.net/~luke/misc/etoys/ (project
files and screenshots). 'XO Adding' is my exercise book for "Add these
two quantities" and Shapes is my "what's the next shape in this
sequence" exercise. I would appreciate pointers to similar projects or
tips for polishing these projects!

I also included my favourite "here's something you can do with Etoys
from scratch" demo, based on a project that I found on squeakland.org
originally, called Ball. The idea is: draw a hill with Paint and make
a circle "roll along" it, initially in a manner so unrealistic that it
*demands* that you improve it, and then with progressively fancier
scripts (doing e.g. acceleration from gravity).

There're a couple of features that I haven't been able to figure out
how to express:

1. In Shapes I'd like to play a sound when the correct shape is
dropped into the answer box. I know how to (re)play the sound all the
time while the answer is correct, but not how to play it once on the
discrete event of the right answer being given.

2. In Ball the 'bouncing' script doesn't work. I'm testing for impact
with the ground using 'Ball's color sees Ground's color' and making
the 'bounce' with 'speed := speed * -0.2'. But this doesn't work right
since if the ball is falling fast it may go a few pixels into the
ground and the first step in the upwards bounces might not get it
clear (in which case it will "impact" again on the next step). I would
like a logical 'and' in the Test box so that impact only happens when
the ball is touching the grand -and- speed > 0.

Tips welcome!

I hope I haven't been too unclear. I'm trying a lot of ideas and
learning more Etoys each day but even so I don't want to do it in
isolation in case I miss some important stuff :-)

Cheers!
-Luke