% === 10.2 ===

dcera(lisa, marge).
dcera(maggie, marge).
dcera(lisa, homer).
dcera(maggie, homer).

syn(bart, marge).
syn(bart, homer).

sestra(Clovek, Ses) :- dcera(Clovek, Rodic), dcera(Ses, Rodic).
sestra(Clovek, Ses) :-   syn(Clovek, Rodic), dcera(Ses, Rodic).

deti(Dieta, Rodic) :- dcera(Dieta, Rodic); syn(Dieta, Rodic).
rodice(Rodic1, Rodic2) :- deti(Dieta, Rodic1), deti(Dieta, Rodic2).

% === 10.3 ===

r(a,b).
r(a,c).
r(b,d).
f1(a).
f1(X) :- f1(Y), r(Y,X).
f2(X) :- f2(Y), r(Y,X).
f2(a).
g1(a).
g1(X) :- r(Y,X), g1(Y).
g2(X) :- r(Y,X), g2(Y).
g2(a).

% === 10.4 ===

% =, ==, =:=, is
%   N is N1 + 2 * 3 / N2
fact(0,   1   ).
fact(Num, Fact) :- Num1 is Num - 1, fact(Num1, Fact1), Fact is Num * Fact1.
% zmensit N o 1, faktorial N-1, vynasobit ho N

% === 10.5 ===

word(astante, a,s,t,a,n,t,e).
word(astoria, a,s,t,o,r,i,a).
word(baratto, b,a,r,a,t,t,o).
word(cobalto, c,o,b,a,l,t,o).
word(pistola, p,i,s,t,o,l,a).
word(statale, s,t,a,t,a,l,e).

crossword(V1, V2, V3, H1, H2, H3) :-
    word(V1, _, F11, _, F12, _, F13, _),
    word(V2, _, F21, _, F22, _, F23, _),
    word(V3, _, F31, _, F32, _, F33, _),
    word(H1, _, F11, _, F21, _, F31, _),
    word(H2, _, F12, _, F22, _, F32, _),
    word(H3, _, F13, _, F23, _, F33, _).