Puzzles

Some more questions to ponder

By jansipke on 2009/05/04

questions

How many two dollar stamps are there in a dozen?
Two mothers and two daughters go to a pet store and buy three cats. Each female gets her own cat. How is this possible?
What building has the most stories?
Six glasses are in a row. The first three are full of juice; the second three are empty. By moving only one glass, can you arrange them so empty and full glasses alternate?
What can you put in a wood box that will make it lighter?
A doctor and a nurse have a baby boy. But the boy’s father is not the doctor and the mother is not the nurse. How can it be?
What is so fragile even saying its name can break it?
While walking across a bridge I saw a boat full of people. Yet on the boat there wasn’t a single person. Why?
When can you add two to eleven and get one as the correct answer?
A basket contains 5 apples. Do you know how to divide them among 5 kids so that each one has an apple and one apple stays in the basket?
Two girls were born to the same mother, on the same day, in the same month and year and yet they’re not twins. How can this be?
A girl who was just learning to drive went down a one-way street in the wrong direction, but didn’t break the law. How come?
Why can’t a man living in the USA be buried in Canada?
One big hockey fan claimed to be able to say the score before any game. How did he do it?
What word describes a woman who does not have all her fingers on one hand?
One brick is one kilogram and half a brick heavy. What is the weight of one brick?
The more there is the less you see. What is it?
How can a woman in New York, without getting a divorce or becoming a widow, or otherwise legally separated, legally marry 10 men?
Many have heard it, but nobody has ever seen it, and it will not speak back until spoken to. What is it?
You are given 18 silver coins but you find out that one of the coins (you don’t know which) is fake and weighs less than any of the others. How can you be able to detect the false coin using a normal balance scale only three times?

Posted in Puzzles Tagged Riddles Leave a Comment

A selection of questions for you to take a stab at. Some of them really simple, others a bit more difficult. If you would like to know the answer to one of these questions, email me at the address listed above.

How far can a dog run into the woods?
Clara Clatter was born on December 27, on a hot summer’s day. How is that possible?
Why are 2004 dollar notes worth more than 2003 dollar notes?
Even when the Arctic natives are starving, why won’t they eat penguin eggs?
Why can’t you take a picture of a man with a wooden leg?
How many birthdays does the average man have?
Some months have 31 days. How many have 28?
How many members of each animal did Moses take on the ark?
How many times can you subtract 5 from 25?
Before Mt. Everest was discovered, what was the biggest mountain in the world?
What is it that people who make it, don’t want it; the people who buy it, don’t use it; and the people who use it, don’t know it?
A man rides into a town on Sunday. Three days later he leaves on Sunday. How can this be?
What’s more powerful than God? The rich don’t want it, the poor have much of it, and if you eat it you die.
Johnny’s mother had three children. The first was named April. The second child was named May. What was the third child’s name?
Can in England a man legally marry his widow’s sister?
Divide 30 by 1/2 and add 10. What is the answer?
If there are 3 apples and you take away 2, how many do you have?
A doctor gives you three pills, telling you to take one every half hour. How many minutes would the pills last?
A farmer has 17 sheep standing in a field and all but 9 drop down and die. How many sheep are left standing?
The butcher in the butcher’s shop is 5′ 10″ tall. What does he weigh?

Posted in Puzzles Tagged Riddles Leave a Comment

Yasumi puzzle

By jansipke on 2001/01/01

Introduction

On this page you can find solutions to the puzzle called Yasumi. It is a game in which different kinds of blocks have to be placed on a grid. Each block is made up of 5 cells each and there are 12 blocks in total. This is exactly the number of unique blocks that can be made up of 5 cells. In the original game these blocks have to be placed on a grid of 6 by 10. Blocks may be rotated if necessary.

In the picture below you can see all the blocks:

yasumi-all-blocks

Solutions to the original game

One of the solutions to the original game is shown in the picture on the left. This is not the only solution to the game; there are actually a lot. I wanted to have all solutions to this game and wrote a computer program to find them. Using brute force alone would not have gotten me very far, because the problem is very complex.

For example, each block (except the red one) can be rotated. The red block cannot be rotated, so there is only one way to place it. The green block can be rotated once, so there are two ways to place it. Five other blocks can be rotated twice, so there are four ways to place them. The last five blocks can be rotated three times, so there are eight ways to place them. Therefore, counting rotations only, there are 1¹ * 2¹ * 4⁵ * 8⁵ equals 67,108,864 ways to place the blocks.

I used backtracking to crack the problem. The function that checks the feasability of the partial solution is crucial to the success of the program. The function I came up with checks whether the size of the open areas in the grid are divisable by 5. If not, then blocks made up of 5 cells cannot be used to fill the open areas. At that point the partial solution can be ignored and another one can be constructed. The program took about 80 minutes on a Pentium II 366 MHz to compile a list of all solutions. If you would like to have the source code, contact me at the e-mail address on this page.

A complete list of the 9356 solutions can be downloaded here: txt (1,206 kB), zip (203 kB).

Solutions to rectangle-shaped grids

The grid used in the original game is not the only one in which the blocks can be placed. Other rectangles have sizes of 5 by 12, 4 by 15 and 3 by 20.

yasumi-rectangle-5-12 4040 solutions: txt (501 kB), zip (78 kB).