Realizing the associahedron: Mysteries and questions
  There are many open problems and some mysteries connected to the realizations of the associahedra as convex polytopes. In this note, we describe three -- concerning special realizations with the vertices on a sphere, the space of all possible realizations, and possible realizations of the multiassociahedron. 
Cesar Ceballos and G\"unter M. Ziegler
math.CO