Squeak Etoys is a "media authoring tool"-- software that you can download to your computer
and then use to create your own media. You can write out your project and share it with others.
Etoys runs on any Mac or Windows machine, as well as on the OLPC XO machine.
It is free.
Find out about Etoys.
Text of this guide (for searching): Paint Tools: Rectangle Tool for
Straight Lines and Right Angles. Click on a paint palette in your
Navigator Bar.
Click the white tab on the lower
right corner to open or close the tools. Select the rectangle. Experiment with the rectangle tool
and all six brush sizes. Draw squares by holding down the
Shift key on the keyboard while using the rectangle tool.