上期IV版：

Day 1 1-4 ABDB Day 2 1-4 CDCD

Day 3 1-4 CADB Day 4 1-4 ABDC

Day 5 1-5 BCDAF

本期II版：

III. The writer’s dad liked four-way stops because he saw them as proof that humans could behave rationally for everyone’s benefit.