Tuesday, July 31, 2007

Brain Teasers

I like brain teasers. I discovered a site with a few fun questions yesterday, and here are some of the questions:

A train leaves New York for Boston. Five minutes later another train leaves Boston for New York, at double the speed. Which train will be closer to New York when they encounter?
If I go halfway to the town (which is 60 km away) at the speed of 30 km/hour, how fast do I have to go for the rest of the way to have the average speed of the entire way 60 km/hour?
These are the conditions in a town:
  1. No two inhabitants have the same number of hairs on their head.
  2. No inhabitant has exactly 518 hairs.
  3. There are more inhabitants than any inhabitant's hair in the town.
What is the highest possible number of inhabitants?
An Arab sheikh tells his two sons to race their camels to a distant city to see who will inherit his fortune. The one whose camel is slower will win. The brothers, after wandering aimlessly for days, ask a wise man for advice. After hearing the advice they jump on the camels and race as fast as they can to the city.

What does the wise man say?
Three masters of logic wanted to find out who was the wisest one. So they invited the grand master, who took them into a dark room and said: "I will paint each one of you a red or a blue dot on your forehead. When you walk out and you see at least one red point, raise your hands. The one who says what colour is the dot on his own forehead first, wins." Then he painted only red dots on every one. When they went out everybody had their hands up and after a while one of them said: "I have a red dot on my head."

How could he be so sure?
Imagine you are in a room with 3 switches. In an adjacent room there are 3 bulbs (all are off at the moment), each switch belongs to one bulb. It is impossible to see from one room to another. How can you find out which switch belongs to which bulb, if you may enter the room with the bulbs only once?
Check out the solutions in the puzzle page! :) Sharpening our mind sometimes helps it works better.

10 comments:

Travel Notes - Photo Slideshow

27/07/07 - Slideshow Status: 50% done.


Note: This post will be placed above other posts as I continue to update my travel notes. My other posts will be found below.

This is the slideshow of the photos taken during the winter trip to Great Ocean Road and South Australia. I am continually processing the pictures and uploading them, so stay tuned as more pictures become available here.

You can also view all the pictures in their original flickr set page here. Full screen slideshow is available as well. To make a comment on an individual picture, visit the "photo link" in the slideshow.

Hope you enjoy the pics!

5 comments:

Monday, July 23, 2007

Some Interesting Harry Potter Endings

J.K. Rowling once said that the last word in the last HP book would be "scar" (which was no longer true in the end). Based on this assumption, some HP fans wrote their own versions of HP ending...

Neville gazed down upon the lifeless form of Harry and saw that the scar that once had stood so vividly on his forehead, had disappeared. He turned away and was unaware that on his forehead, was his own scar.
His thoughts were distracted by the distant voices of Hermione and Ron. They were running towards him with mixed looks of shock and relief. Hugging Harry they began to question him thoroughly. "Are you alright? Are you okay Harry?" Hermione yelled. "Blimely Harry you've done it, Voldemorts dead." Ron added. As if it went by in flashes, suddenly Hermione and Ron were on the ground, both pale and motionless, dead. Harry stood over them, laughing coldly with content. All it took was a twinge in his scar.
Harry had done it... Voldemort was dead it seemed... but there were only five horcruxes that had been destroyed. Ron raised his head from the ground and said, "Good work, Harry, I knew we could do it..." Harry smiled to Neville while scratching his itching scar.
More endings here.

I am wondering how different the story would be if it ended like above... :)

2 comments:

Sunday, July 22, 2007

An Intriguing Game

Unfortunately the world works just like this game. Sometimes we imagine, if everyone obeys traffic rules, the traffic congestion would be dramatically reduced. But people break the rules. If every country in the world destroys their nuclear weapons, this will be a much safer world. But we will never live to see a day with a nuclear-free world. If everyone unites and strive for the greater good, this will be a much better world. But human won't unite. The reason? The same as in this game. As long as there are competitions, there will be "good" and "bad" people who assume their own niches in the equilibrium of the complex net of interactions. Game theory dictates it.
Game theory is fascinating. Since I first learnt about it some years ago, I have been absolutely enchanted by how it seems to apply to everything in this world - including, but not restricted to animal behaviours (including human's), evolution, cultural revolution, economics, politics, nuclear warfare, global warming treaties etc. The implications of game theory just seem to pop up everywhere.

What is game theory?

Game theory is just what it says - the theory of games. Examples of theory of games could range from anything as simple as how to tackle tic-tac-toe, to what happens when two players play checkers perfectly (which was solved just recently). However, in its modern word usage, game theory is not about winning and losing in a table-top game (which is in the field of combinatorial game theory) - it's more about everything that involves competition, everything that involves different parties aspiring to maximize their own return (among others). Basically this covers almost every organic interaction. Games, in the context of game theory, are played between countries and populations.

Consider this interesting game:

An investment game is played in a group of 4. In each round of the game, each player will make a choice of investing 10 dollars or investing nothing. At the end of each round, the sum of the investment by the four players is pooled together, and each player (regardless of the amount he has invested) will get 40% of the sum in the pool. For example, if everyone invests 10 dollars, then there will be 40 dollars in the pool, and therefore everyone will get 16 dollars at the end which means a 6-dollar profit.

By doing some analysis, the outcomes of the game can be described as follows:
4 x 10 dollars: Everyone earns 6 dollars - a total profit of 24 dollars.
3 x 10 dollars: 3 player who invested will earn 2 dollars, the person who didn't invest earns 12 dollars. A total profit of -6 dollars.
2 x 10 dollars: The 2 investing players LOSE 2 dollars, the 2 non-investing players earn 8 dollars each. A total profit of 12 dollars.
1 x 10 dollars: The investing player LOSES 6 dollars, the 3 non-investing players earn 4 dollars each. Total profit of 12 dollars.
0 x 10 dollars: Nobody invests, nobody earns or loses anything. Total profit is zero.

At the first glance of the game, it seems that it would be ideal if everyone just keeps on investing in every round - that would be the best outcome, everyone earns and the total profit is the highest. However, a few rounds into the game, someone might realize - hey wait, if the other three players continue to invest and I stop, I will earn 12 dollars, more than the previous scenario! And hence some people will stop investing. Then some other player may stop investing as well, and now the two non-investors get 8 dollars, at the expense of the investors' loss! In some rounds everyone might get selfish, and it ends up as the 0 x 10 dollar case - at this point some people realize that someone has got to invest to keep it going. So in the end the game will bounce somewhere between all the scenarios, but it will not stay at the 4 x 10 dollars, the supposedly best option for everyone.

Unfortunately the world works just like this game. Sometimes we imagine, if everyone obeys traffic rules, the traffic congestion would be dramatically reduced. But people break the rules. If every country in the world destroys their nuclear weapons, this will be a much safer world. But we will never live to see a day with a nuclear-free world. If everyone unites and strive for the greater good, this will be a much better world. But human won't unite. The reason? The same as in this game. In this page, you can see how the theory behind this game applies to real-life scenarios, ranging from political science, economics to athletic competitions.

As long as there are competitions, there will be "good" and "bad" people who assume their own niches in the equilibrium of the complex net of interactions. Game theory dictates it.

p/s: Yes, this game is a variation of the
prisoner's dilemma.

4 comments:

Harry Potter and the Deathly Hallows - A Haiku

Warning: The following text contains spoilers (indirect but VERY decipherable). It has been hidden by scripts and would be revealed when it's clicked on. However, the hiding mechanism doesn't work on RSS reader, so if you are reading this on RSS subscription and if you do not wish to read it, STOP. Thanks.

Show my haiku!



Perched between two worlds
A forgotten, burdened soul
The evil hero.

- Dedicated to Severus Snape who didn't get the salute he deserved in the very end.

5 comments:

Friday, July 20, 2007

Travel Notes (2) - Great Ocean Road

I've been processing the pictures from the road trip, but I found it rather difficult to reproduce the whole journey on my blog if I were to do a stop-by-stop descriptions. So I guess I would start with a few pictures here.

DSC08111a
Xuan Ni and I at Gibson's Steps, with the backdrop of Twelve Apostles.
DSC08105a
The glory "apostles" at the Twelve Apostles. It's my third time there but it invigorates me all the same.
DSC08114
Yong Chin, Freda, Xuan Ni and I at Gibson's Steps.
Facial expression: "What's in stock for the future?"

3 comments:

Wednesday, July 18, 2007

Don't Read This: Harry Potter Spoilers!

As we all know, the final book of Harry Potter series "Harry Potter and the Deathly Hallows" is coming out this Saturday, and there have been wild speculations about the ending by fans throughout the world. However, those speculations are all over the place, and it makes everything so hard to find. So, to put all of them in one place, I present to you: the 13 most interesting "spoilers" out there about Harry Potter!

Warning: If you haven't read the previous six books and intend to read them in the future, then this really is NOT for you. If you have read the previous six books, then it's fine. I will hide the following list so that nobody would read it by accident. To read it, just click on the link below.

Show the spoilers!
  1. Snape kills Dumbledore
  2. DUMBLEDORE COMES BACK TO LIFE AND KILLS SNAPE PAGE 505
  3. Hermione is a DUDE
  4. Bush declares war on Hogwarts!
  5. Trinity dies.
  6. Snape dies
  7. Syrius Black dies. Oh wait....that's what happened in the movie.
  8. Everyone dies.
  9. The series ends.
  10. Harry Potter almost dies at the end, but realizes that the whole story was a bad dream. He wakes up back in the house of the horrible family, father banging on the closet door.
  11. 299 died
  12. Gollum falls into fires of Mordor with the ring.
  13. Darth Vader is Harry's father.


Hah, I know some of them are rather lame, but many did crack me up. :)

By the way, this is a gentle warning to all Harry Potter fans: if you want to avoid spoilers, please avoid all form of human contacts from the time you get the book until you finish the last page. Spoilers are going to be all over the place, in your email, comment in every unrelated blog article, friends' conversations, phone calls, online chat etc. There are just way too many sadistic people who enjoy seeing people agonise over spoilers. When the last book came out, someone witnessed a crazy guy who went into the bookstore lines, read the last few pages, and yelled the ending. Another person heard people yelling out the window when he was in the bookstore's parking lot. Crazee people.

For me, the sixth book got spoiled last time because I overheard people commiserating with each other over the event. Arrgh. This Saturday I am going to join the line, cover up my ear, get the book quickly, go offline, ignore SMS and avoid friends. Nobody's going to spoil it this time.

8 comments: