I am a mathematics teacher at a junior high school. When I was a college student I met a professor who is studying mathematics using Visual Basic. After graduation I have been developing teaching materials with that skill. However, as a weakness of Visual Basic, there was a beautiful depiction that did not make the dot feel, and a representation of the watermark. Also, I was curious that it only worked on Windows.
　At that time I met GeoGebra. It does not require a difficult programming language. Everyone can use the teaching materials developed by people all over the world. And it was wonderful to work with all OS.
　However, when using teaching materials in lessons, I thought that it would be a loss of time every time I visited GeoGebra's HP. So I made this HP. People who share the same feeling, please use freely within the range of common sense.