More than 20 years ago, a graduate student of mine, named Beth, (surname escapes me, but she had triplets and is a very fine high school math teacher) used an early version of MicroWorlds to program her own version of a toolkit similar to Geometer’s Sketchpad. Over time, I ran a similar activity with kids as young as 7th grade. I’ve done my best to piece together various artifacts from my archives into a coherent starting point for this potentially expansive activity. Hopefully, you’ll be able to figure out how to use the tools provided and improve or expand upon them.
Students (middle and high school) will use MicroWorlds EX create their own tool for exploring two-dimensional geometry similar to Geometers’ Sketchpad, Cabri, or GeoGebra. 
As students build functionality (via programming) into a tool for creating and measuring geometric constructions, they reinforce their understanding of important geometric concepts. As the tool gets more sophisticated, students learn more geometry, which in turn leads to a desire to explore more complex geometric issues. This is an ecological approach to programming. The tool gets better as you learn more and you learn more as the tool becomes more sophisticated.
Along the way, students become better programmers while using variables, list processing, and recursion in their Logo procedures. They will also engage in user interface design.
- Teacher and student project instructions
- MicroWorlds EX Geometry Toolkit starter template file
- An example of a more elaborate Geometry Toolkit created by Beth
 I would not show commercial models of the software to students until after they have programmed some new functionality into their own tools.
Veteran educator Gary Stager, Ph.D. is the author of Twenty Things to Do with a Computer – Forward 50, co-author of Invent To Learn — Making, Tinkering, and Engineering in the Classroom, publisher at Constructing Modern Knowledge Press, and the founder of the Constructing Modern Knowledge summer institute. He led professional development in the world’s first 1:1 laptop schools thirty years ago and designed one of the oldest online graduate school programs. Gary is also the curator of The Seymour Papert archives at DailyPapert.com. Learn more about Gary here.