Tower diagrams and Pieri's rule

We introduce an algorithm to describe Pieri's Rule for multiplication of Schubert polynomials. The algorithm uses tower diagrams introduced by the authors and another new algorithm that describes Monk's Rule. Our result is different from the well-known descriptions (and proofs) of the rule by Bergeron-Billey and Kogan-Kumar and uses Sottile's version of Pieri's Rule.