Saturday, July 20, 2013

A chess post

To improve one's chess play, reading books and famous games is an established but boring way to improve your skill. So I have resorted to playing continuously instead  which is far more entertaining but also far slower. Since the last month I started playing I have played 500 (!!) 10 min games on chess.com .

Occasionally I look at famous games. My amateur chess expert has advised me to look at the games of Paul Morphy first. I started looking at the games but then I realized that although improving is only possible when you analyze games, it is far more rewarding and easier to analyze your own games. I played this interesting chess game  recently. I am going to analyze my own and my opponent's mistakes from the principles I have gathered. Please post improvements/suggestions in comments.

Also since its turning out to be very difficult to include a dynamic chess board on blogger, I am just including the link to the game here : game?id=561308873 .

I am playing white in the above game. The winner makes the last mistake here, as always.

Black's second move seems intimidating. The bishop on b4 pins my d4 pawn. I don't know what the best defense to this is, so I move my knight and hope to quietly slip my bishop in d2 as in move 5. (I don't want the bishop to take my knight and destroy my pawn structure).

Normal development follows till move 9. White's 9. o-o is weakening. Black could have played 9. .. Bxc3, and after that 10 .. Bxe2. To defend that white should have played 9. Nd5 forking the Queen and the bishop.

Black's Queen remains on the open e-file for too long for white to play tactics such as 11. Bxa6 . Black's move 16 is also restricting. Qf5 would be better since it maintains pressure on the d4 square while providing the Queen room to move. Similarly white 17. Qe1 should have been Qe2, since it backs both the white knight and bishop.

A better move for white instead of 18. d5 would be Bd5.

Now 24. Ne5 leaves black  with little choice. The only move to protect a mate would be Qf5 or Qg5. Both of which is countered by g4.

Sunday, July 7, 2013

Experiments with Neodymium magnets

I bought a set of neodymium to play with. When you are bored, without a computer, they come in handy.

The set consisted of 216 small 4-5mm balls of magnets. The magnets came in a 6x6x6 shaped cube. That shape was very unstable and stuck to the metallic box. On trying to break apart the cube the cube disintegrated into chains.

Trying to put back the magnets into a cube is not very easy. I can say that, because my friend, a physicist, also failed at the first attempt. Here's my approach and the difficulty I face along with the tricks involved.

My approach was to create a stack of 6 rings of the spheres each ring consisting of twelve balls.
Three stacks are required to make a cube. Here what the stacks looked like.
Now I flattened out all the stacks and formed sheets of 6x6x2,
Now I just stuck the stacks together and I had my cube.


The problem

The problem was to get a stack to align properly. Actually, there are two possible ways,

Proper (left) and improper (right) alignment
The one on the left is the desired one.

Proper (top) and improper (bottom) alignment

Also all the three stacks must align properly, although you don't have to combine those stacks. Because otherwise the 6x6x2 sheets would not stick together to form a cube. One of the sheets would slide over the other similar to the bottom chains in the above figure.

The trick
Suppose you are trying to join two stacks of rings and just would not align properly. The trick is to flip one stack and then try again. There's a catch here. If both of the stacks consist of even number of rings, flipping won't work. So adding rings one by one to a stack always works.

Suppose now you have formed three stacks of rings, all properly aligned. But all the three stacks do not align properly and so you cannot stick the respective sheets together. Here, atleast two stacks must be aligning properly and the third one would not align with any of the other two. So instead of  trying to re-create the third stack ad hoc, if all the rings of the third stack are inverted, it works. 

Here's the underlying diagrams.
Magnets aligning to form rings
The spheres colored regions inside the spheres represent the north and south poles of the magnet. So if two different configurations are superimposed they align properly, otherwise flipping one of them works. 
But suppose instead of a ring we have stacks of even number of rings ( both aligned properly ), flipping does not change the configurations of the stack and hence they will always align wrong. So inverting a ring, as follows, is required.
Inverting a ring
Inverting a ring (or stack of rings)

Here are some more configurations. Interestingly, the hexagon is more stable than the cube.