It’s the Friday Puzzle!

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Here is the Friday puzzle!  Solution on Monday.

The day before yesterday Joan was 17.  Next year she will be 20.  How can that be the case?

I have produced an ebook containing 101 of the previous Friday Puzzles! It is called PUZZLED and is available for the Kindle (UK here and USA here) and on the iBookstore (UK here in the USA here). You can try 101 of the puzzles for free here.

Does this dot change size?

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Jerome H sent me this great animated Ebbinghaus illusion…..amazingly the orange circle stays the same size!

 

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I think it originates here, along with lots of other cool stuff.

UPDATE: Re the origin, of this, Stan noted:

One week ago at the Vision Sciences Society meeting in Florida was the annual visual illusions Hollywood style competition of the 10 best illusions of the year. They will be featured in Scientific American Mind. It already has a Wikipedia entry at http://en.wikipedia.org/wiki/Ebbinghaus_illusion. The last sentence of that entry is:
“The winner of the 2014 Best Illusion of the Year Contest, submitted by Christopher D. Blair, Gideon P. Caplovitz, and Ryan E.B. Mruczek, of the University of Nevada Reno, animated the Ebbinghaus illusion, putting it in motion.”

 

 

It’s the Friday Puzzle!

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First, alas I won’t be able to make it to the Amazing Meeting this year because of a clash of dates.  Sorry about that.  It’s a wonderful convention, and if you are into science and skepticism it’s a great place to be.

OK, here is the Friday puzzle!  Solution on Monday.

John and Joan decide to play several games of cards, with a stake of £1 per game.  After several games John has won three games and Joan has won £3.  How many games did the two of them play?

I have produced an ebook containing 101 of the previous Friday Puzzles! It is called PUZZLED and is available for the Kindle (UK here and USA here) and on the iBookstore (UK here in the USA here). You can try 101 of the puzzles for free here.

Answer to the Friday Puzzle….

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coverOn Friday I set this puzzle.  If you have not tried to solve it, have a go now.  For everyone else the answer is after the break.

Imagine that you have a coin that is biased – that is, in a long series of tosses it won’t come up with 50% heads and 50% tails.  Alas, you don’t know the extent of the bias.  How can you use the coin to generate a random series of zeros and ones?

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It’s the Friday Puzzle!

coverHere is the Friday puzzle!  Solution on Monday.

Imagine that you have a coin that is biased – that is, in a long series of tosses it won’t come up with 50% heads and 50% tails.  Alas, you don’t know the extent of the bias.  How can you use the coin to generate a random series of zeros and ones?

I have produced an ebook containing 101 of the previous Friday Puzzles! It is called PUZZLED and is available for the Kindle (UK here and USA here) and on the iBookstore (UK here in the USA here). You can try 101 of the puzzles for free here.