procedure main(A)    # Compute all forward difference orders for argument list
    every order := 1 to (*A-1) do showList(order, fdiff(A, order))
end

procedure fdiff(A, order)
    every 1 to order do {
        every put(B := [], A[i := 2 to *A] - A[i-1])
        A := B
        }
   return A
end

procedure showList(order, L)
    writes(right(order,3),": ")
    every writes(!L," ")
    write()
end