/Parallelism in Space/
Theorem 2 (The test for skew lines)
Theorem 3b (Transitivity of parallelism)
Theorem 4 (The test for parallelism of a line to a plane)
Theorem 6 (The test for parallelism of two planes)
Representation of a parallelepiped
Representation of a prism.
Representation of a triangular pyramid
Representation of a regular triangular pyramid
Representation of a quadrilateral pyramid
Parallelism in Space. Movie.