A zonotope and a product of two simplices with disconnected flip graphs
  We give an example of a three-dimensional zonotope whose set of tight zonotopal tilings is not connected by flips. Using this, we show that the set of triangulations of $\Delta^4 \times \Delta^n$ is not connected by flips for large $n$. Our proof makes use of a non-explicit probabilistic construction. 
Gaku Liu
math.CO math.MG