GAP 4.8.9 installation with standard packages -- copy to your CoCalc project to get it
gap> START_TEST("HAP library");
gap> Read(Concatenation(dir,"bing.txt"));
gap> BingsHouse;
Regular CW-complex of dimension 2
gap> BingsModifiedHouse;
Regular CW-complex of dimension 3
gap> Size(BingsHouse);
309
gap> Size(BingsModifiedHouse);
311
gap> Size(ContractedComplex(BingsModifiedHouse));
1
gap> Size(ContractedComplex(BingsHouse));
309
gap> STOP_TEST( "tst.tst", 1000 );