Line segments MJ and JK appear to be perpendicular.
Line segments JK and KL appear to be perpendicular.
Line segments KL and LM appear to be perpendicular.
Line segments LM and MJ appear to be perpendicular.

Line segments MJ and LK appear to be parallel.
Line segments JK and ML appear to be parallel.

Each face of a cube is a square.
Opposite sides of a square are parallel.
Adjacent sides of a square are perpendicular.

Edges 1 and 3 are perpendicular.
Edges 2 and 4 are perpendicular.

Edges 1 and 2 are parallel.
Edges 3 and 4 are parallel.