The next meeting of the UK Smalltalk User Group will be on Wednesday, September 29th. For this month's meeting, we take a look at an example of an application written in Smalltalk. Specifically, one that fits in a cultural tradition that is as old as Smalltalk itself, if not older: that of using computers as tools to teach powerful ideas and to augment thinking. Dr. Geo is an interactive geometry software with programming capabilities in Smalltalk. Dr. Geo aims to be an open, easy to study, modify and extend interactive geometry software. Ten years old kids use Dr. Geo to explore Euclidean geometric sketches; agile kids extend and program it with its embedded dynamic Pharo language and user interface. Hilaire Fernandes started the development of Dr. Geo in 1996. In 1998, he ported it to GNU/Linux at a time where no interactive geometry software existed on this system. It latter became officially a GNU application blessed by Richard Stallman. In the spirit of free software and acce