Recursion with an Arbitrary Number of Lists
{ apple, banana }
{ milk, cheese, yogurt }
{ nuts, legumes }
— would result in —
{ apple, milk, nuts }
{ apple, milk, legumes }
{ apple, cheese, nuts }
{ apple, cheese, legumes }
{ apple, yogurt, nuts }
{ apple, yogurt, legumes }
{ banana, milk, nuts }
{ banana, milk, legumes }
{ banana, cheese, nuts }
{ banana, cheese, legumes }
{ banana, yogurt, nuts }
{ banana, yogurt, legumes }
