2simplices:=
 [[1,2,5], [2,5,8], [2,3,8], [3,8,9], [1,3,9], [1,4,9],
 [4,5,8], [4,6,8], [6,8,9], [6,7,9], [4,7,9], [4,5,7],
 [1,4,6], [1,2,6], [2,6,7], [2,3,7], [3,5,7], [1,3,5]];;
K:=SimplicialComplex(2simplices);;
K:=RegularCWComplex(K);;
Y:=DirectProduct(K,K);;
C:=ChainComplexOfRegularCWComplex(Y);;
D:=ChainComplex(Y);;
Print(List([0..4],C!.dimension),"\n");;
Print(List([0..4],D!.dimension),"\n");;
Print(Homology(D,2),"\n");;