Bongard problem (5)

The Russian scientist M.M. Bongard published a book in 1967 that contains 100 problems. Each problem consists of 12 small boxes: six boxes on the left and six on the right. Each of the six boxes on the left conform to a certain rule. Each and every box on the right contradicts this rule. Your task, of course, is to figure out the rule.

You can check your solutions here

You can find more Bongard problems at Harry Foundalis site, and I intend to publish more problems in the future.

A new puzzle is posted every friday. You are welcome to comment on the puzzles. Solutions are added at the bottom of a puzzle after one or more weeks.

The 4 cards (Cont’d)

The brainteaser of the 4 cards is a nice teaser, which made me wonder if it could be generalized. Indeed I found a couple of ways to vary upon this theme.

1) The 3 values
There are six cards in front of you. Each of them has a letter on one side and a number on the other side. Three of them have letters face up: A, B and C. The other three have numbers face up: 1, 2 and 3.
How many cards (and which) do you want to check if you want to know every card with ‘C’ on the front face has a ‘2’ on the reverse?

You can check your solutions here

2) The three triangular blocks
Another way to vary on this subject is to have more than one backside. Consider the wooden blocks depicted in this figure. They have three sides (plus a top and a bottom). One side has a letter, one side a color and one side a number. Only one side is facing you. You can only rotate them clockwise. You are not allowed to get up and walk around them.
As you can see, each block now has two ‘backsides’, a leftback and a rightback. The letter is either A or B, the number either 1 or 2, and the colour either orange or purple.



As you can see there is an ‘A’, a ‘2’ and an ‘Orange’ facing you.

How many rotations do you have to make to ascertain if the rightback of all B is purple?

You can check your solutions here

Bongard problem (3)

The Russian scientist M.M. Bongard published a book in 1967 that contains 100 problems. Each problem consists of 12 small boxes: six boxes on the left and six on the right. Each of the six boxes on the left conform to a certain rule. Each and every box on the right contradicts this rule. Your task, of course, is to figure out the rule.

Here is an example:

You can check your solutions here

You can find more Bongard problems at Harry Foundalis site, and I intend to publish more problems in the future.

Inspector Simon Mart and the stolen toupet

Inspector Simon Mart looked out of the window of his familiar office room. What he saw was very familiar: nothing. Or, more precisely: the well known grey of London smog. It looked like a particular dense smog, as he could not even see the tree at the other side of the street, nor the pedestrians or traffic in the street below.

He would much, much rather have been at the sun drowned beaches of a tropical archipellego, but he was here back in London.
And he’d better get to work. He looked at the interrogation reports of the three criminals. The toupet of major Big Boaster had been stolen. The three criminals were all so rotten that none of the three could utter three sentences without speaking the truth more than once. Luckily, it had already been established that one of them was the thief.

Their interrogation reports:
Picking Pete: Rotten Ray is innocent. Thoughtless Theo is the thief. I am innocent.
Rotten Ray: To his dismay inspector Mart found that some thoughtless secretary had spilled coffee over this interrogation report, and it was completely unreadable.
Thoughtless Theo: Picking Pete is innocent. I am innocent. Rotten Ray is the thief.

Inspector Simon Mart got himself some tea from the coffee maachine and found that it tasted just like one can expect from a coffee machine: the tea tasted as coffee.
Still, he managed to conclude who the thief was. Can you?

You can check your solutions here

A new puzzle is posted every friday. You are welcome to comment on the puzzles. Solutions are added at the bottom of a puzzle after one or more weeks.

The 4 cards

Before you are four cards on the table. The front side has an ‘A’ or a ‘B’ on it. The back has a ‘1’ or a ‘2’ on it. As you can see, two cards show their front side, and the other two cards show their back side.
A friend of mine thinks that on the back of every card with a ‘B’ there is a ‘2’.
Which card(s) do you turn to test his hypothesis?

This is not an original problem, and the source is unknown to me. I guess it is from somewhere in the twentieth century. I was recently reminded of it when thumbing through James Fixx “More games for the superintelligent”, a mensa publication. I hope to get back to this puzzle in a later post.

You can check your solutions here

Tectonics

The free Dutch daily newspaper Metro recently – I think it was in september – published a new type of puzzle calles tectonics.
The puzzle area usually is a rectangle, for example 4×5, which is subdivided into areas of size 1 to 5. An area of size 1 contains just the number 1, an area of size 2 contains the numbers 1 and 2, and so on, until an area of size 5 which contains the numbers 1, 2, 3, 4 and 5 exactly once.
A second rule is that the same number may never be adjacent: not horizontally, not vertically, and not diagonally.
Note that there is no rule that a number may appear just once in a row or column.

A complete filled tectonic may look like:

The puzzles in Metro are designed by Denksport, the largest puzzle publisher in the Netherlands. In the magazine shop I discovered a magazine with these puzzles.
Tectonic puzzle booklet can be ordered here. I think the order page is only in Dutch, and I’m not sure if you can mail order from abroad.

Nr 1)^*

Nr 2)^*

Nr 3)^**

You can check your solutions here, here, and here.

The publisher claims that these puzzles are a new international rage. That may well be true, but a quick search on “tectonic puzzles” turned up just puzzles on plate tectonics.

Bongard problems (2)

The Russian scientist M.M. Bongard published a book in 1967 that contains 100 problems. Each problem consists of 12 small boxes: six boxes on the left and six on the right. Each of the six boxes on the left conform to a certain rule. Each and every box on the right contradicts this rule. Your task, of course, is to figure out the rule.

Here is an example:

You can check your solutions here

You can find more Bongard problems at Harry Foundalis site, and I intend to publish more problems in the future.

Bongard problems (1)

The Russian scientist M.M. Bongard published a book in 1967 that contains 100 problems. Each problem consists of 12 small boxes: six boxes on the left and six on the right. Each of the six boxes on the left conform to a certain rule. Each and every box on the right contradicts this rule. Your task, of course, is to figure out the rule.

Here is a trivial example:

Here is something more resembling a puzzle:

You can check your solutions here

You can find more Bongard problems at Harry Foundalis site, and I intend to publish more problems in the future.

The two squares (1)

What code corresponds with the figure in the centre?

You can check your solutions here

Inspector Simon Mart and the stolen matchsticks

Inspector Simon Mart looked at the old sign on the door of his office with his name: Inspector Mart, S. That his parents had bestowed just one initial on him, had been one of his life long irritations. He probably should have told his parents before his birth that he wanted many birth names. But perhaps he could persuade the guys who provided the signs on the doors that his initial should precede his family name, and not come after it. Well, he had his own room and that was a benefit that should last until the next reorganization.

His manager had dumped a file on his desk. He read the attached note: ‘to be solved last month’. It was the 29th of the month, and he decided that this urgency would allow him to start with a mug of coffee and a social chat with his fellow inspectors at he coffee machine. At the coffee machine he met a new and pretty police officer and he chatted for a quarter of an hour with her. After that chat he decided to pick up this file. It contained a number of reports as well as a copy of interrogations. He summoned that a couple of matchsticks encrusted with amethysts had been stolen from the London Matchbox Museum. There were three suspects, Jim, Jack and John, all well known criminals. It was known that none of them could speak two consecutive true statements. He looked at the interrogation reports:

Jim: Jack did it. John is innocent.
Jack: John did it. Jim is innocent.
John: Jim is innocent. Jack is innocent.

You can check your solutions here