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**MathsIsFun****Administrator**- Registered: 2005-01-21
- Posts: 7,535

Here is my first draft of Cross Number Puzzles

Suggestions and comments welcome.

"The physicists defer only to mathematicians, and the mathematicians defer only to God ..." - Leon M. Lederman

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**bobbym****Administrator**- From: Bumpkinland
- Registered: 2009-04-12
- Posts: 86,776

Hi MathsisFun;

Nice game. I think two features are needed.

1) An increase board size option, I had a little trouble seeing it.

2) Numbers can be input using the numeric keypad too. When I tried I got letters instead of numbers.

**In mathematics, you don't understand things. You just get used to them.Of course that result can be rigorously obtained, but who cares?Combinatorics is Algebra and Algebra is Combinatorics.**

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**phrontister****Real Member**- From: The Land of Tomorrow
- Registered: 2009-07-12
- Posts: 3,848

Hi MathsIsFun,

Easy, intuitive operation. Nice beginners' puzzle.

Like with Bobby's computer, my number pad types letters into the grid.

Suggestion:

1) Have two levels of difficulty, and for the harder level don't change the font colour for solved clues.

2) Maybe include a calculator window (probably not really necessary, but some players may find it handy).

3) Include a list of definitions for clues where there may be some doubt or ambiguity, and to explain tricky terms or terminology (shouldn't be needed for easy puzzles).

In the draft puzzle that I played:

a) "Ascending digits" looked for an answer containing ascending *consecutive *digits (eg, 2345 but not 1235: both answers satisfy "Ascending digits", but only the first answer satisfies "Ascending consecutive digits");

b) 4 across had two solutions (512 and 152). I can't access that particular puzzle anymore, but I think the clue read "Rearrange digits of 8 down". 4 down's third digit was already solved and the other two came from 8 down's "5" & "2"...but there was no constraint for a unique solution.

*Last edited by phrontister (2011-02-15 00:20:23)*

"The good news about computers is that they do what you tell them to do. The bad news is that they do what you tell them to do." - Ted Nelson

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**MathsIsFun****Administrator**- Registered: 2005-01-21
- Posts: 7,535

Thanks guys! Good suggestions.

The program actually checks that you followed each clue, so multiple solutions are possible.

I need to write a guide to explain everything

It would be far more challenging if I didn't provide the first answer.

"The physicists defer only to mathematicians, and the mathematicians defer only to God ..." - Leon M. Lederman

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**bobbym****Administrator**- From: Bumpkinland
- Registered: 2009-04-12
- Posts: 86,776

It would be far more challenging if I didn't provide the first answer.

What first answer? You mean one was given to me...

**In mathematics, you don't understand things. You just get used to them.Of course that result can be rigorously obtained, but who cares?Combinatorics is Algebra and Algebra is Combinatorics.**

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**MathsIsFun****Administrator**- Registered: 2005-01-21
- Posts: 7,535

The one with the clue "Two Digits" ... what if they were not given? Too hard?

"The physicists defer only to mathematicians, and the mathematicians defer only to God ..." - Leon M. Lederman

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**bobbym****Administrator**- From: Bumpkinland
- Registered: 2009-04-12
- Posts: 86,776

Not for phrontister! This one took me over nine minutes!

**In mathematics, you don't understand things. You just get used to them.Of course that result can be rigorously obtained, but who cares?Combinatorics is Algebra and Algebra is Combinatorics.**

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**phrontister****Real Member**- From: The Land of Tomorrow
- Registered: 2009-07-12
- Posts: 3,848

Hi MathsIsFun,

I've only briefly tried one of the puzzles by removing the first clue. I couldn't solve it logically as there were too many open doors I couldn't shut...which would mean solution by trial and error, which I don't like. Also, I prefer puzzles with a unique solution.

Here's a link to a download of XFigure, which is a nice crossnumber generator with many options.

It used to feature in a computer magazine that I subscribed to, which I bought mainly to enter the XFigure puzzle contest. I won that once and received a pathetic digital videocam/camera that I sold for $250...which paid for quite a few subscriptions!

I've got XFigure on my computer and have generated some nice, fairly hard puzzles with it (customized).

Maybe it could be useful for ideas for your game.

Have you considered changing the "Ascending digits" clue to "Ascending consecutive digits"?

*Last edited by phrontister (2011-02-16 12:46:30)*

"The good news about computers is that they do what you tell them to do. The bad news is that they do what you tell them to do." - Ted Nelson

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**MathsIsFun****Administrator**- Registered: 2005-01-21
- Posts: 7,535

Thanks phrontister. You won a contest in this kind of puzzle? My Goodness Gracious!

I haven't looked at XFigure, but it sounds really good.

I have just posted v0.66, which allows for 5 "hints", and different size grids.

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**mathsyperson****Moderator**- Registered: 2005-06-22
- Posts: 4,900

Nice page! I love this kind of puzzle, where all the clues refer to each other and you need to search for a foothold to get started.

One thing that annoyed me was that you can't turn a cell blank after you've entered something into it.

It'd be nice to get rid of numbers that you realise could be wrong.

Why did the vector cross the road?

It wanted to be normal.

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**MathsIsFun****Administrator**- Registered: 2005-01-21
- Posts: 7,535

Good point. I will look at that.

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**bobbym****Administrator**- From: Bumpkinland
- Registered: 2009-04-12
- Posts: 86,776

Hi MIF;

It is much tougher now! The arrow keys moving to the next box up, down or right left would speed up input.

Of course that result can be rigorously obtained, but who cares?

Combinatorics is Algebra and Algebra is Combinatorics.

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**MathsIsFun****Administrator**- Registered: 2005-01-21
- Posts: 7,535

Latest Update (0.662):

* use delete or space to clear an input.

* up, down, left, right work ... but don't move into "black" territory.

(Phew .. you guys make me sweat, hope I am not adding bugs!)

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**bobbym****Administrator**- From: Bumpkinland
- Registered: 2009-04-12
- Posts: 86,776

Hi MIF;

Good job! Works fine for me.

Of course that result can be rigorously obtained, but who cares?

Combinatorics is Algebra and Algebra is Combinatorics.

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**phrontister****Real Member**- From: The Land of Tomorrow
- Registered: 2009-07-12
- Posts: 3,848

Hi MathsIsFun,

There a problem with the clue numbering in the large grid, which I noticed when I started this puzzle (below).

I think the other two grid sizes are ok.

*Last edited by phrontister (2011-02-17 20:53:08)*

"The good news about computers is that they do what you tell them to do. The bad news is that they do what you tell them to do." - Ted Nelson

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**MathsIsFun****Administrator**- Registered: 2005-01-21
- Posts: 7,535

Thanks phrontister, that is a weird one, it is sort of half right. I will look into it.

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**phrontister****Real Member**- From: The Land of Tomorrow
- Registered: 2009-07-12
- Posts: 3,848

Hi MathsIsFun,

I did a Medium one tonight (see uncompleted version below). Doing it without using any hints or a first-clue answer certainly made it much more challenging than before!

I solved it on paper and then checked five of my answers against the hints...all ok.

Btw, I had expected that one of the hints - probably the first - would have given the first-clue answer you provided before, but 11 Across "Two digits" missed out. That's probably good for maintaining the higher difficulty, as giving the answer to that clue probably provides an easier solution path than the other hints would.

Also, as far as I can tell, the solution is unique.

*Last edited by phrontister (2011-02-18 04:15:25)*

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**MathsIsFun****Administrator**- Registered: 2005-01-21
- Posts: 7,535

All good news!

And I have fixed the numbering, too.

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**phrontister****Real Member**- From: The Land of Tomorrow
- Registered: 2009-07-12
- Posts: 3,848

Hi MathsIsFun,

I just completed a game from the Hard level (see starting grid below). No hints were used.

The solution is unique.

All the fixes are good! I didn't come across any bugs so far, and the game plays well.

*Last edited by phrontister (2011-02-20 02:19:37)*

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**MathsIsFun****Administrator**- Registered: 2005-01-21
- Posts: 7,535

Very Excellent!

At some time in the future I would like to revisit it, and add more clue types. Such as "3 across squared", "2 down divided by 4"

And I could have a new "Simple" class of puzzle where clues are like "4x12" or "days in 3 weeks".

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**phrontister****Real Member**- From: The Land of Tomorrow
- Registered: 2009-07-12
- Posts: 3,848

MathsIsFun wrote:

I would like to...add more clue types. Such as "3 across squared", "2 down divided by 4".

Here's a sample from some crossnumber puzzles I've got:

A factor of 11A

Two more than a factor of 17A

Multiple of 26D

Square

Cube

Quadruple

Palindrome

Palindrome composed of odd digits

Prime number

Anagram of a cube

Number followed by its square

Number followed by its double

Number preceded by its cube

Number preceded by an anagram of its square

Reverse of a square

Equally descending digits

Ascending digits

Consecutive squares

Consecutive prime numbers

Product of its digits is 24

Product of 23A and 26D

Contains only even digits

Square composed of squares

Contains just the unique digits of 37A

Composed of distinct even digits

One less than a prime number

Sum of the digits is twice the first digit

Difference between adjacent digits increases

Sum of the digits is a factor of their product

Less than 15D

Middle digit is the product of the other two

Difference between adjacent digits is, in some order or other, 1, 2, 3 and 4

Unique digits, each divisible by 3

A quarter of this gives the first two digits of 9A

As you can see from some of the clues, the puzzles they're from are hand-crafted rather than computer generated.

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**phrontister****Real Member**- From: The Land of Tomorrow
- Registered: 2009-07-12
- Posts: 3,848

Hi MathsIsFun,

Here's a puzzle I just completed from the Hard level. No hints used, and the solution is unique.

I wonder if solutions to all the puzzles (or maybe only the hard ones) are now unique. Maybe it's only coincidence because I've only done two from that level, but neither had multiple solutions.

I like the print option, because I prefer to solve the puzzles on paper.

*Last edited by phrontister (2011-02-21 00:07:15)*

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**MathsIsFun****Administrator**- Registered: 2005-01-21
- Posts: 7,535

There is an underlying answer, but the program does not check for uniqueness. So I validate your answers against the clues, in case you find an alternate correct answer. I think most of those alternate answers are a result of "loose" clues like "ascending digits".

Thanks for the list, it may come in handy!

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