#const lasttime=1.

bucket(a;b).
%amount(1..1).
amount(1..2).
time(0..lasttime).

volume(a,0) $== 0.
volume(b,0) $== 1.

down(X,T) :- volume(X,T) $> volume(Y,T), bucket(X;Y), time(T).
up(X,T) :- volume(X,T) $< volume(Y,T), bucket(X;Y), time(T).
balance(T) :- volume(X,T) $== volume(Y,T), bucket(X;Y), X != Y, time(T).

volume(B,T+1) $== volume(B,T) + A :-     pour(B,T,A), bucket(B), time(T), T<lasttime, amount(A).
volume(B,T+1) $== volume(B,T)     :- not pour(B,T),   bucket(B), time(T), T<lasttime, amount(A).

pour(B,T) :- pour(B,T,A).

1{ pour(X,T,A) : bucket(X) : amount(A) } 1 :- time(T).

:- up(a,lasttime).


%volume(B,T) $>=0 :- bucket(B), time(T).
%volume(B,T) $<10 :- bucket(B), time(T).

$domain(0..100).

#hide bucket/1.
#hide time/1.