block(a).
block(b).
block(c).

time(t0).
time(t1).
time(t2).
time(t3).



on(a,b,t0).
on(b,table,t0).
on(c,table,t0).

goal(T) :- time(T), 
	on(b,c,T),
	on(c,a,T).



