Here is the index to the individual puzzles:
 December 28 |
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January 1 |
Now's your chance: all the way until midnight January 15th (in Samoa = UTC/GMT –11 hours) you can send in your solutions or comments to all the ChessBase Christmas puzzles (including the brain teasers) of the past week. Please use this feedback form to do so. It is important that you include your full name, your place of residence and a return email address (which will never be published or given to a third party). The following prizes are up for grabs:
The book by John Nunn will have a personal dedication for the winner; the other three programs have signatures of World Champions, past and present, and other historical chess personalities. Full solutions and the names of the winners will be published after the 15th of January.
Note that we have received very few solutions to the final brain teaser posed by John Nunn at this year's London Chess Classic: an explorer reaches a cross-road where one path leads to the the village, in which food and refuge await, and one to the jungle, where he would be torn to bits by wild animals. Three men are standing at the cross-road, a liar, a truth teller and an idiot. The latter answers yes or no completely at random, whatever you ask him. You have two yes-no questions to find the path to the village. Submitting a solution to this logical problem will increase your chances of winning a prize.
Remember the amazing optical illusion we showed you some years ago?
Can you believe that the squares marked A and B in the above picture are exactly the same shade of grey? You can't? Then take a look at our proof here.
In a follow-up on December 31, 2005 we showed you the above illusion: Would you believe that the "brown" square in the middle of the top surface is exactly the same colour as the "yellow" square in the middle of the front surface? As a colleague at the time commented: Yikes!
Now we take this one step further:
Cross your heart: would you believe that the "blue" corner cube in the left image is the same colour as the "yellow" one next to it in the right image? Seriously – exactly the same colour and shade. Copy the picture to a paint program, cut a piece out of the left image and move it to onto the right-hand one. That is the only way you can convince yourself that they are the same.
