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

length (list :: [ NoDup () ])  =  2

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

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

tiers :: [NoDup ()]  =
  [ [NoDup []]
  , [NoDup [()]]
  ]