**Parallel lines** are lines which do not intersect.

**Perpendicular lines** are lines which intersect at right angles.

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.