Monthly Archives: September 2012

Dollar auction


John Smith has come up with a perfect plan to get rich: he is gonna auction dollar notes, but with a twitch. The dollar note will be won by the highest bidder, as usual, but the next highest bidder also has to pay his bid.

Now if you wonder how this is gonna make him money, let’s consider how an auction is likely to develop. It is obvious worthwhile to bid 1 cent, so someone will likely do that. It is also profitable to overbid this with 2 or 5 cents, so let’s say someone else will bid that. prices will go up. But a problem develops near the 100 dollar cent limit. Let’s say someone hits 98 cents. Someone else bids 99 cents. Then the person with the 98 cents bid will loose 98 cents unless he bids 100. And then the first person, who is about to loose 99 cent, is better off by a bid of 101 cent.

Now, how can you, as one of the bidders, outsmart John Smith?

Fellow consultant Con Diender was kind enough to buy me the booklett “Einstein’s riddle”, by Jeremy Stangroom. Though I think the title is not accurate – the zebra puzzle is a puzzle, not a riddle – it is an interesting collection of problems. The problem above was mentioned in this book, though the author gives an incomplete or incorrect answer.

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Endview, Edgeview


Edgeview or Endview or “ABC End view puzzle” is the name of a popular class of logic puzzles. The english language wikipedia calls it Buchstabensalat, but gives no source for this name, and I frankly believe this is a mistake. I have seen it called Endview, though personally I prefer the name edgeview. At the time of writing, the arguments ‘endview puzzle’ gives 18.600 hits, buchstabensalat 16.000, but often with a different meaning or with an explanation that this is an “ABC end view puzzle”. It appeared in many world puzzle championships.

I’m not sure who invented this type of puzzle, or when. I think I have seen it around for a few decades.

In a 4×4 square grid, every row and column contains the letters ABC and one empty space. Along the edges of the grid, some cells are filled with the first letter seen from that cell.

1) 4×4
The following puzzle has an A, B, C and empty space in every row and column.
4x4

2) 5×5
This puzzle has A, B, C and two empty spaces in every row and column:
5x5

3) 6×6
There are an A, B, C, D and two empty spaces in every row and column:
6x6

If you solved it, we have the solution to 1, solution to 2 solution to 3for you.