---
title: "C.a.R."
chunk: 1/1
source: "https://en.wikipedia.org/wiki/C.a.R."
category: "reference"
tags: "science, encyclopedia"
date_saved: "2026-05-05T12:13:42.587198+00:00"
instance: "kb-cron"
---

C.a.R. (Compass and Ruler), also known as Z.u.L. (Zirkel und Lineal), is a free and open source interactive geometry app that can do geometrical constructions in Euclidean and non-Euclidean geometry.
The software is Java based.
The author is René Grothmann of the Catholic University of Eichstätt-Ingolstadt.
It is licensed under the terms of the GNU General Public License (GPL).


== Assignments ==
Assignments make possible to create Java applets, for a construction exercises.
These applets can be used from the command line using the AppletViewer.
(Previously, they could be run in a browser, but Java support in browsers has been disabled in recent years.)


== See also ==

GeoGebra
CaRMetal
Compass-and-straightedge construction


== External links ==
C.a.R.
History of the C.a.R.