The Penrose triangle, an impossible-looking shape, is made by welding metal pipes together. First, the metal pipes are cut ...

Two congruent angles are simply pairs of angles with equal measures. You can find congruent angles examples in hundreds of everyday objects.

Main purpose of the GeometRi library is manipulations with basic geometrical primitives, such as point, line, plane, sphere, triangle in 3D space: translation and rotation operations, distance ...