Pairwise (All-Pair) Testing
Pairwsie testing (or all-pair testing) is used to test every possible discrete combinaison of values.
The goal is to reduce the number of test to its minimum will still behing exhaustive, and this before the end of the world (or before your company runs out of money).
Creating pairwise combination is possible by hand but it’s also a field where computer excels so better let them do that.
A great tool to create pairwise combination is PICT, or Pairwise Independent Combinatorial Testing by Microsoft.