None, not ever, nohow.
A diamond has two pairs of parallel lines.
A rhombus has 2 pairs of parallel lines.
A parallelogram has two pairs of opposite congruent lines
A regular dodecagon has six pairs of parallel lines.
it has 2 pairs of parallel lines
4 pairs
0 pairs
2 pairs
A square has 2 pairs of equal opposite parallel lines
A regular octagon has four pairs of parallel lines.
Can have no pairs or one pair...
2 pairs