[Haskell-beginners] foldr with ($) as the passed function

[Lawrence Bottorff]

With 99 questions <https://wiki.haskell.org/99_questions/Solutions/3> Problem
3 wants a function elementAt that will take a list and an index and return
the element for that index. One very odd version in the solutions is

elementAt xs n = head $ foldr ($) xs $ replicate (n - 1) tail

So the function "passed" is ($) and the accumulator "seed" is the incoming
list xs and the list to be worked on is (replicate (n-1) tail) which . . .
and I can't fathom what's happening -- other than perhaps (replicate (n-1)
(tail xs))

elementAt [1,2] 2 would be

foldr ($) [1,2] (replicate 1 (tail [1,2])
foldr ($) [1,2] ([2])

. . . now I'm lost. Can someone walk me through this?

LB
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