Use the Programmer's File Editor to create a file called family.pl. Launch the program and create a new file window from the File menu.
When you have created a new file window, type the following, being particularly careful to type exactly what appears here, including full stops and commas:
male(harry).
female(liz).
parent(phil, chas).
parent(liz, chas).
parent(chas,harry).
parent(chas,wills).
grandmother(GM, C):-
mother(GM, P),
parent(P, C).
mother(M,C):-
female(M),
parent(M, C).