"Stencils allow children to explore the math behind the patterns. It is difficult for them to perceive the difference between 1/8 and 3/8 without visual aids in the beginning. Unlike charts, Etoys is interactive. Unlike paper or cardboard, it allows children to repeat any number of times without waste."
- K.K. Subramaniam (who created the Stencil code in squeak to make this possible) 

Fraction A Day - Day 33+ Half a Spongebob allows kids to create there own fractions using stencils and a line drawing tool. Video demo here


Also there is beautiful use of the stencils by Susanne Guyader, an 80+ year old artist who used Squeak/Etoys to guide art teachers in France. 
http://community.ofset.org/index.php/Grab_area_button

A big thanks to Subbu for the squeak code to make this possible.

Stephen