/prog/ challenge [HASKELL]

Use the loeb function:
loeb :: Functor a => a (a x -> x) -> a x
loeb x = fmap (\a -> a (loeb x)) x

To implement a basic spreadsheet processor. The processor should accept input of the form:
|##|A        |B    |C   |D       |
|01|(* B1 C1)|2    |3   |(* A1 2)|
The output from this example should be:
|##|A      |B    |C   |D     |
|01|6      |2    |3   |12    |
Cells may contain number literals, references to other cells of the form <letter><number>, or function applications of the form (<function> *<args>).

new challenge: write the loeb function in a language that isn't haskell, and use it to do something useful.