  InfoMod is a new software and application devoted to the modular group,
PSL2(Z). It has algorithms that deals with the classical correspondences among
continued fractions, geodesics on the modular surface and binary quadratic
forms. In addition the software implements the recently discovered
representation of Gauss' indefinite binary quadratic forms and their classes in
terms of certain infinite planar graphs (dessins) called \c{c}arks. InfoMod
illustrates various aspects of these forms, i.e. Gauss' reduction algorithm,
the representation problem of forms, ambiguous and reciprocal forms. It can be
used as an educational tool, and might be used to explore some new facts about
these objects.
