gap> F:=ReadImageAsFilteredPureCubicalComplex(file,500);;
gap> L:=[20,60,61,62,63,64,65,66,67,68,69,70];;          
gap> T:=FiltrationTerms(F,L);;
gap> P0:=PersistentBettiNumbers(T,0);;
gap> BarCodeCompactDisplay(P0);
gap> P1:=PersistentBettiNumbers(T,1);;
gap> BarCodeCompactDisplay(P1);
