Bunch of hoon toy problems

find_vowels.hoon

|=  n=tape
=/  index  0
=/  found  ""
=/  vowels  "aeiou"
|-
?:  =(index (lent vowels))
  found
=/  current  (trip (snag index vowels))
=/  added  ?:  =(~ (find current n))
  ""
current
%=  $
  index  +(index)
  found  (weld found added)
==

flop.hoon

|=  [l=(list)]
^-  (list)
=/  i  (dec (lent l))
|-
=/  next  ?:(=(i 0) ~ $(i (dec i)))
[(snag i l) next]

nth_fib.hoon

|=  n=@ud
^-  @ud
=/  a  0
=/  b  1
|-
?:  =(n 0)
  a
%=  $
  a  b
  b  (add a b)
  n  (dec n)
==

nth_square.hoon

|=  n=@ud
^-  @ud
=/  b  1
|-
?:  .=  n  1
  %-  pow  :-  b  2
%=  $
  b  (add 1 b)
  n  (dec n)
==