You wake up in a room. There are two doors, one to your right, and one to your left. One leads to Heaven, and the other, Hell. Obviously, you cannot tell which door leads where. But there are also 4 statues in the room, all sculpted from gold. They are fashioned in the exact same way, each of them infinitely identical to the next. But you remember an old folktale about this very room from when you were a lad: All of these statues are the only beings in existence with all the answers to everything. They know everything there is to know about any subject.
One statue tells nothing but the truth.
Another statue tells nothing but lies.
The third and fourth statues base what they will say upon each other: they both tell the truth 50% of the time, and lies the other 50%.
Now, if the third statue is asked a question first, and it responds with the truth, then the fourth statue will be forced to answer with a lie, and vice-versa. Also, if the fourth statue is asked a question first and it answers with the truth, the third will be forced to answer with a lie, and vice versa.
(Keep in mind, there is no specific order to these statues, I call them in order merely for introductory reasons. They are not lined up in any specific order and you have no way of telling which is which through looking at them.) You are allowed to ask each door 1 question. Follow these rules, and try to reach Heaven.