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

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