?- brother(charles,andrew).
true .

?- brother(trump,charles).
false.

?- brother(edward,X).
X = charles ;
X = anne ;
X = andrew ;
X = charles ;
X = anne ;
X = andrew ;
false.

?- grandchild(Who,elizabeth).
Who = william ;
Who = harry ;
Who = peter ;
Who = zara ;
Who = beatrice ;
Who = eugenie ;
Who = louise ;
Who = james ;
false.

?- ancestor(Foo,eugenie).
Foo = andrew ;
Foo = sarah ;
Foo = elizabeth ;
Foo = philip ;
Foo = george ;
Foo = mum ;
false.

?- son(X,philip).
X = charles ;
X = andrew ;
X = edward ;
false.

?- son(X,george).
false.

?-