Nice one Petr & Dick.

Looking though old old threads a minute ago and saw 'shortest joke' thread ..... which reminded of the (supposedly) shortest clue in a crossword.....

gge (9,3)

To confirm, it says gge.

Jonhinkansas, I'm surprised that I only confused you a bit !!!!

A simpler variation on the original scenario :

Plain room, two doors & two twins as before. You know The liar guards the door to hell, the truth-teller guards the door to heaven. You have only one question, 'they' only answer yes/no.

So what question do you ask ???

Personally rather than go through all the what if's/nand/nors etc I would ask a question all 3 of you KNOW the answer to eg Is he(she) your twin ? Have I asked you a question ? Can I get to heaven if I ask the right question ? But that's pobably deemed cheating.

Hilary