  We show that indecomposable two-term presilting complexes over $\Pi_{n}$, the
preprojective algebra of $A_{n}$, are in bijection with internal $n$-simplices
in the prism $\Delta_{n} \times \Delta_{1}$, the product of an $n$-simplex with
a 1-simplex. We show further that this induces a bijection between
triangulations of $\Delta_{n} \times \Delta_{1}$ and two-term silting complexes
over $\Pi_{n}$ such that bistellar flips of triangulations correspond to
mutations of two-term silting complexes. These bijections are shown to
compatible with the known bijections involving the symmetric group.
