Björner's example of non-extendably shellable 2-polyhedron

Description
This strange example was made by Björner. This is shellable but not extendably shellable.
Identify the vertices with the same labling. That is, this example is made from a projective plane and one additional triangle.
Properties
The smallest example which is shellable but not extendably was found by Moriyama and Takeuchi, with 6 vertices and 9 facets. That this Björner's example has non-zero homology and that it has no boundary should be remarked.
Datum
bjorner.dat
Some table
vertex decomposable?yes
extendably shellable?no
shellable?yes
constructible?yes
Cohen-Macaulay?yes
partitionable?yes
topologyprojective plane + one facet
f-vector(1,6,15,11)
h-vector(1,3,6,1)
made byBjorner

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