The Cartesian Product of
                      LEFTTAB and RIGHTTAB

  Continent  Export    Country   Continent  Export    Country
  ------------------------------------------------------------
  NA         wheat     Canada    NA         sugar     USA     
  NA         wheat     Canada    EUR        corn      Spain   
  NA         wheat     Canada    EUR        beets     Belgium 
  NA         wheat     Canada    ASIA       rice      Vietnam 
  EUR        corn      France    NA         sugar     USA     
  EUR        corn      France    EUR        corn      Spain   
  EUR        corn      France    EUR        beets     Belgium 
  EUR        corn      France    ASIA       rice      Vietnam 
  EUR        rice      Italy     NA         sugar     USA     
  EUR        rice      Italy     EUR        corn      Spain   
  EUR        rice      Italy     EUR        beets     Belgium 
  EUR        rice      Italy     ASIA       rice      Vietnam 
  AFR        oil       Egypt     NA         sugar     USA     
  AFR        oil       Egypt     EUR        corn      Spain   
  AFR        oil       Egypt     EUR        beets     Belgium 
  AFR        oil       Egypt     ASIA       rice      Vietnam