[Prolog]
Write a predicate `peaks(Lst, Ps)` that is true if Ps is the list of all elements in Lst that are strictly larger than their preceding and succeeding elements. Note that the
first and last element never satisfy this condition. For example,
`peaks([1, 5, 3, 4, 0, 5, 6, 4], X).`
results in `X = [5, 4, 6]`.