map length (tiers :: [[ X Nat7 ]])  =  [1,1,1,1,1,1,1]

length (list :: [ X Nat7 ])  =  7

allUnique (list :: [ X Nat7 ])  =  True

ratioRepetitions (list :: [ X Nat7 ])  =  0 % 1

tiers :: [X Nat7]  =
  [ [0]
  , [1]
  , [2]
  , [6]
  , [3]
  , [4]
  , [5]
  ]
