What is GeCla?

GeCla, short for Generator and Classifier, is a program which is associated with the DVD Symmetry - the dynamical way, but whose use does not assume that one knows this DVD. GeCla allows the user to generate a pattern, a frieze or a rosette with a previously chosen kind of symmetry starting from an asymmetric motif. It also allows the classification (with or without help from the program) of the patterns, friezes, rosettes obtained in this manner. In the end, the program provides a report of the errors committed. GeCla was designed in a different spirit from the previous DVD, in particular attempting to be attractive and accessible to students of various levels of education. GeCla already has versions in five (PT, EN, IT, GE, SP) of the six languages represented on the DVD, and the other one (FR) is in preparation.

The generator writes encoded information about the existing symmetries in the jpg image file generated. Then the classifier reads and interprets this coded information, which allows it (according to the level of aid chosen) to give information about how the classification process is going, preventing wrong choices, or only indicating at the end whether the classification is correct and, if not, indicating the first mistake.

GeCla also includes a competition option that can be used via the Internet. In it, each player generates a pre-agreed number of images and then both exchange images and each classifies the other's images. All steps are managed by the program, which in the end provides a report on eventual mistakes. As a platform for managing the transmission of files generated during the competition, you can use Dropbox or an equivalent system. A chat allows message exchange during the game.

In early June 2013, a first competition was organized between Portuguese students of a school in Valadares and Italian students from a school in Besozzo. See references in the Gazeta de Matemática, X’la Tangente and in Educação e Matemática.

There are already schools (at least) in Portugal and Italy, wanting to repeat that experience and Atractor is available to support the logistics and to promote and facilitate contacts.