None, not ever, nohow.
A diamond has two pairs of parallel lines.
it has 2 pairs of parallel lines
A parallelogram has two pairs of opposite congruent lines
A regular dodecagon has six pairs of parallel lines.
A rhombus has 2 pairs of parallel lines.
2 pairs
0 pairs
4 pairs
A regular octagon has four pairs of parallel lines.
A square has 2 pairs of equal opposite parallel lines
3 equal sides
up to four pairs is the answer