C.a.R.
C . a . R . – Compass and Ruler ( also known as Z . u . L . , which stands for the German "Zirkel und Lineal" ) — is a free and open source interactive geometry app that can do geometrical constructions in Euclidean and non-Euclidean geometry . 
<triplet> Euclidean <subj> geometry <obj> part of <triplet> non-Euclidean <subj> geometry <obj> part of