DaveG38

This is how it works. Point to one door and ask each robot the question 'if I ask you if this is the door to safety would you say yes.' Assume the door I point to is the safe one. The truthful robot will simply say yes, he would say this because it is true. The lying robot says to himself, I know that the door pointed to is the safe one, but because I'm a liar I would say no. But then the rest of the question asks whether he would say yes to his own lying answer. Logically, the robot being a liar will directly contradict his earlier 'no' answer so he says yes to the question, since he is lying about his own earlier lie. Hence both robots indicate which is the correct door and so you can escape. Works the other way round for the wrong door. This has always been my understanding of the puzzle, but if anybody knows different please say. PS: Missed the answers already given, which have a greater logic. My answer was predicated on a slightly different version, whereby a man is walking through the jungle and comes to a fork in the road. There is a native at the fork. One arm of the fork leads to safety and the other to certain death in the alligator swamp. The man knows that some natives always lie and others always tell the truth, but there is no way he can determine which type of native he has encountered. As before what one question can he ask to determine the way to safety?

You can ask a conditional question. By doing so you ensure that it doesn't matter whether the robot being asked is a liar or atruth teller. So you ask ' if I ask you if this is the safe door, would you say yes.'

Thank you for that - I didn't realise it was that simple.

All, Does anybody know who the eBay dealer '1.10TH' is? Thanks

No good for me - its not gluten free!!

Personally, I'm overwhelmed with indifference.

Were you one of the ba+*^rds at PERME, who demonstrated explosives to my team as part of our counter-sabotage training? The army guys used small amounts of explosives and det cord to blow up various bits of telecomms plant, such as cable etc. (I worked for BT at the time in the early 1980s). When they showed us what the effect of home made explosives (Co-op) on steel plate the results were impressive, but made more so by the army guys tossing gravel on top of the shelter we were in, to simulate shrapnel from the bunker where the explosions occurred. Anything to scare those lily-livered civilians!

I don't mind a few adjustment marks, but I draw the line at obliteration of part or all of the date.

My 1967 dot on trident penny is feeling quite left out and unloved.

Duh!! Smacks forehead in gesture of stupidity.

Definitely Alan Hunt. He has been sending me catalogues by email for a number of years now.

I last had a catalogue from him about 6 months ago. In the past I have bought high grade maundy from him, but from memory the last catalogue was mostly hammered.

In the early 1980s they went to fortnightly for a while, then reverted back to monthly. I would assume from this that this was their peak sales period, but that fortnightly just didn't work out.

Fair enough. I wasn't really criticising, just lamenting the need for some better information.

Pity he couldn't include some illustrations of the kinds of fakes to look out for, or maybe a reference to any websites where these are shown.

Just looked through my Feb 1992 copy - all 66 pages of it. There are several references to future articles: Bottom of Page 7 - In Search of A Precursor - Part III - overdates and their precursors. P31 - In 'Market Movements' they planned to cover 2d, 11/2d, 1d and 1/2d in March. P40 - Still asking for coin lists, catalogues to be sent in for compiling the 'Market Movements' tables. P56 - Part 2 of 'The Gods of The Hindus' was to be included in the March edition. From this, I guess there was an abrupt end to the business - given the low sales they achieved in later years this isn't a surprise. In practice the mag was published on the second Thursday of the month preceding the cover date, and the March edition was planned to be published on 13 Feb 1992. This means that whatever occurred took place sometime between mid January and mid February 1992.

Well done that man!!! From memory, I don't recall seeing any advance notice suggesting there would be no March edition, but I'll go and hook it out and have a browse through it. Won't take long as it got thinner and thinner as the years went by. Again, many thanks for this info.

From a timing point of view, based on my own collection of Coin Monthly magazines, it seems likely that the last issue of the magazine was February 1992. If that is the case, then it is likely that there was no Coin Monthly Yearbook after this as the business folded, i.e. there would be no 1993 issue, which would normally have been worked on leading up to the end of that year. That would leave an obvious gap in the market, which Coin News may have picked up on, but they would not have been able to react quickly enough to put a yearbook out for 1993, so they were forced to do so in 1994.

You just got unlucky. Royal Mail don't examine everything that comes into the UK, but on this occasion they chose something of yours. I've probably bought several hundred coins from the US over the years, but I have only been caught for customs duties etc. on a couple of occasions. It's a lottery!

I have considered the idea of digitising the entire series of Coin Monthly and publishing them online for collectors to use. It's a hell of a task, and one that I would be happy to do (slowly) if I could be sure that there are no copyright issues. Unfortunately, when I tried to establish ownership of the copyright that proved to be a very tricky task, and so I abandioned the idea, even though I believe it would be very worthwhile.

As I think I said earlier, the last one I have is Feb 1992. I've never seen anything newer. A few years ago, I knew a lady who used to proof read for the magazine, but sadly she couldn't help either.

I've only got 12/66 and 01/67 I'm afraid. Most of my spares seem to cover the 1980s and 1990s. If you PM me your name and address, I'll send these two on. No charge. I'm happy to see a couple leave my crowded cupboard!

For reverse C, the top of the crown on the Irish harp points to a bead and the rim is very thin, whereas on reverse E, the top of the crown points to a space and the rim is thicker. There are other identifiers, but these should be enough for high garde examples.

From memory, I think the first issue was about November 1966. If you are interested, I have quite a lot of spares, where I purchased bulk lots to complete the set, and have many duplicates.

You could keep both, as the top example appears to be Rev E, whilst the bottom one looks like Rev C.