The fork facing the sultan's army
bin Hassad, an ancient Arabic mathematician was a guest of the sultan of a territory he was passing through.
"O bin Hassad, famed wise man! Holder of the Logical Eye! I have a problem which I can trust you to help me with", said the sultan. "In any way I can Sultan! I am your guest and I am at your service", declared bin Hassad
"Well", said the sultan, "A batallion of my army has just come to a fork in its pursuit of a very hostile gang of criminals. On one way of the fork is the sign:
The other sign is true and this path is the way forward.
On the other fork is a sign that says:
The sign on the other path is false and the way forward is behind that sign
"How shall I advise my army, there is no time to waste time?" pleaded the sultan. "Have a rest, it is hot, come and tell me your solution afterwards."
"O Sultan! Host greater than water is scarce in the desert, I will do what you ask and come up with the answer" said bin Hassad, as a servant of the sultan came to attend to him and lead him to the guest villa.
bin Hassad did not really need to sleep on this problem, but he did not want to hurt his host's feelings. So he delayed his answer till after the rest period. What did bin Hassad advise?