Pairwise Combinations Generator
This is not generating correct pairwise combinations.

Input data

[['Requests'],
    ['Create','Edit'],
    ['Contact Name','Email','Phone','Subject','Description','Status','Product Name','Request Owner','Created By','Modified By','Request Id','Resolution','To Address','Account Name','Priority','Channel','Category','Sub Category'],
    ['None','is','isn\'t','contains','doesn\'t contain','starts with','ends with','is empty','is not empty'],
    ['Contact Name','Email','Phone','Subject','Description','Status','Product Name','Request Owner','Mark Spam','Resolution','To Address','Due Date','Priority','Channel','Category','Sub Category']]


Result by Microsoft PICT

http://pastebin.com/cZdND9UA

Result by your code
http://pastebin.com/EC6xv4vG

This generates only for NONE in most of cases such as this

Requests    Create  Account Name    None    Category
Requests    Create  Account Name    None    Channel
Requests    Create  Account Name    None    Description
Requests    Create  Account Name    None    Due Date