map length (tiers :: [[ NoDup Nat2 ]])  =  [1,1,1,2]

length (list :: [ NoDup Nat2 ])  =  5

allUnique (list :: [ NoDup Nat2 ])  =  True

ratioRepetitions (list :: [ NoDup Nat2 ])  =  0 % 1

tiers :: [NoDup Nat2]  =
  [ [NoDup []]
  , [NoDup [0]]
  , [NoDup [1]]
  , [ NoDup [0,1]
    , NoDup [1,0]
    ]
  ]