We show that indecomposable two-term presilting complexes over $Π_{n}$, the preprojective algebra of $A_{n}$, are in bijection with internal $n$-simplices in the prism $Δ_{n} \times Δ_{1}$, the product of an $n$-simplex with a 1-simplex. We show further that this induces a bijection between triangulations of $Δ_{n} \times Δ_{1}$ and two-term silting complexes over $Π_{n}$ 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.