Pentagrammic antiprism
In geometry, the pentagrammic antiprism is one in an infinite set of nonconvex antiprisms formed by triangle sides and two regular star polygon caps, in this case two pentagrams.
This polyhedron is identified with the indexed name U79 as a uniform polyhedron.
An alternative representation with hollow centers to the pentagrams.
Net (fold the dotted line in the centre in the opposite direction to all the other lines): 
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