  The topological string partition function for the neighbourhood of three
spheres meeting at one point in a Calabi-Yau threefold, the so-called 'closed
topological vertex', is shown to be reproduced by a simple Calabi-Yau crystal
model which counts plane partitions inside a cube of finite size. The model is
derived from the topological vertex formalism. This derivation can be
understood as 'moving off the strip' in the terminology of hep-th/0410174, and
offers a possibility to simplify topological vertex techniques to a broader
class of Calabi-Yau geometries. To support this claim a flop transition of the
closed topological vertex is considered and the partition function of the
resulting geometry is computed in agreement with general expectations.
