# Overview

C.a.R. is dynamic geometry program. Basically, it simulates compass and ruler constructions on a computer.

But on a computer, much more is possible.

- Ruler and compass constructions can be changed by
**dragging**one of the basic construction points. The construction follows immediately. The student can**check**the correctness of the construction and gain new**insight**. **Tracks**of points and animated constructions can help to understand geometric relations. Tracks can be used as new objects to explore with intersections and points fixed to the tracks.- With the
**macros**of C.a.R. very complicated constructions become possible. Macros are also a way to organize the geometric thinking. **Hiding**construction details and using colors make constructions clearer to read. In C.a.R. lines and circles can also be reduced to the relevant points.- Arithmetic
**expressions**, numerical**solutions**,**curves**and**functions**go beyond classical constructions. It is even possible to construct in 3D using advanced macros. - Other geometries,
**hyperbolic**or**elliptic**, can be explored.

C.a.R. works on all modern platforms. Constructions and assignments can be embedded into web pages easily. C.a.R. has been translated in many languages. C.a.R. can be used free of charge, and the source is available under the Gnu General License.