The appeal of this puzzle is, of course, that it appears to have insufficient information for the solution. Also, an intriguing point is that the first statement is true -- UNTIL S articulates it. Then it becomes false.

The Tower of Hanoi puzzle has three sticks in a line. Over the first stick are five rings on top of each other, all different sizes, largest at the bottom, small rings on top of larger rings.

Can you move the rings one at a time until they appear in the same order on the stick at the other end. Smaller rings must always stay on larger rings.

There is a square of 36 spaces. You have 14 bottles. Every row and column has to have an even number of bottles. Can it be done?

Circle of Sim

This is a game. Draw a circle with six points on it, evenly spaced out. Two players have a different coloured pen each. Take it in turns drawing lines between the two dots. The loser is the first person to draw a triangle in their colour.

A man has a fox, a hen and some seed. He must taken them across a river in a boat, but the boat can only hold the man and one other item. Can the man take the fox, hen and seed across, never leaving the fox with the hen or the hen with the seed?

There are four men who want to cross a bridge at night, by the light of a flashlight that one of them has. They all begin on the same side and the bridge can only hold two of them at once. They all walk different speeds and take different amounts of time to cross the bridge, namely: 1,2,5 and 10 minutes.

Whenever two of them are on the bridge together they must walk at the pace of the slower person. Any party who crosses the bridge must carry the flashlight, and the flashlight must be walked back to the other side to bring over any remaining people. The flashlight cannot be thrown etc.

For example if the 1 minute man and the 10 minute man walk across, 10 minutes have elapsed when the get to the far side. If the 1 minute man then crosses back with the flashlight, a total of 11 minutes have elapsed, and there are still three people on the wrong side of the bridge.

Describe how they all cross in 17 minutes.

Answer

Three light switches control three upstairs lights. When you click the switches you cannot see which switch controls which light. You know all the lights are off when the switches are up. You are allowed just one visit upstairs, then you have to say which switch matches which light. How can you do it?

Everyone likes a boiled egg but cooking them for just the right time is difficult. In this case, the egg needs to be boiled for nine minutes. The problem is you only have a four-minute and a seven-minute egg timer at your disposal. How can you ensure that you boil the egg for exactly nine minutes using only these two timers?

Answer

You have a pair of balancing scales and various items needing to be weighed. Each item is an exact unit of measure. You have three weights to help perform the task, and you can choose how heavy each weight is. What is the highest value you can weigh, given that you must be able to calculate the weight of any items below that weight?

There is a prison with 100 cells and in each cell there is 1 prisoner. At the prison there is a prisoner to guard ratio of 1:1. The lock on the door mean that when you turn the key once you change the status of the lock and if you then turn it again you change it back to how it was. For example if it starts locked and a guard turns the key the lock would then be open, if the key is turned again the door is then locked.

All the doors start locked with the prisoners in the cells. The first guard walks past and turns the key in every lock, the 2nd guard turns the lock on the 2nd, 4th, 6th etc door. The 3rd guard turns every 3rd lock, the fourth every 4th lock. This goes on to the hundredth guard only turns the lock in the 100th door. The guards all then go to bed

Which cells would you want to be in to guarantee escaping and why can this be determined without going through the process with each of the hundred guards.

A logician on holiday in the South Seas finds himself on an island inhabited by the two proverbial tribes of liars and truth-tellers. Members of one tribe always tell the truth, members of the other always lie. He comes to a fork in the road and has to ask a native bystander which branch he should take to reach a village. He has no way of telling whether the native is a truth-teller or a liar. The logician thinks a moment, then asks one question only. From the reply he knows which road to take. What question does he ask?

I have a circular sponge that I would like to divide between eight people equally. I can do it in just three slices - how do I do it?

Everyone in a restaurant is sick, but it isn't the fault of the cook - what happened?