A knotted 2-dimensional foam with non-trivial cocycle invariant
  By 2-twist-spinning the knotted graph that represents the knotted handlebody $5_2$, we obtain a knotted foam in 4-dimensional space with a non-trivial quandle cocycle invariant. 
J. Scott Carter (Univ. of South Alabama), Atsushi Ishii (Univ. of   Tsukuba)
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