  We introduce a class of combinatorial singularities of Lagrangian skeleta of
symplectic manifolds. The link of each singularity is a finite regular cell
complex homotopy equivalent to a bouquet of spheres. It is determined by its
face poset which is naturally constructed starting from a tree (nonempty finite
acyclic graph). The choice of a root vertex of the tree leads to a natural
front projection of the singularity along with an orientation of the edges of
the tree. Microlocal sheaves along the singularity, calculated via the front
projection, are equivalent to modules over the quiver given by the directed
tree.
