Challenge Questions Blog

Challenge Questions

Stop in and exercise your brain. Talk about this month's Challenge from Specs & Techs or similar puzzles.

So do you have a Challenge Question that could stump the community? Then submit the question with the "correct" answer and we'll post it. If it's really good, we may even roll it up to Specs & Techs. You'll be famous!

Answers to Challenge Questions appear by the last Tuesday of the month.
Previous in Blog: A Cat Dreams of Mice (March 2025 Challenge Question)   Next in Blog: The Will of A Will (May 2025 Challenge Question)
Close

Comments Format:






Change Mode
Close

Subscribe to Discussion:

CR4 allows you to "subscribe" to a discussion
so that you can be notified of new comments to
the discussion via email.

Close

Rating Vote:







Add Vote
9 comments
Rate this Comments: Nested

Fire Spiral (April 2025 Challenge Question)

Posted March 31, 2025 12:00 AM
Pathfinder Tags: challenge question

The accompanying diagram depicts 35 matches arranged in a spiral. Move 4 matches to create 3 squares.

Answer (4.24.25)

See the second image in Randall's post below.

Reply

Interested in this topic? By joining CR4 you can "subscribe" to
this discussion and receive notification when new comments are added.

Comments rated to be Good Answers:

These comments received enough positive ratings to make them "good answers".

Comments rated to be "almost" Good Answers:

Check out these comments that don't yet have enough votes to be "official" good answers and, if you agree with them, rate them!
5
Randall
Guru

Join Date: Aug 2005
Location: Hemel Hempstead, UK
Posts: 5811
Good Answers: 317
#1

Re: Fire Spiral (April 2025 Challenge Question)

03/31/2025 5:51 AM

Dammit: I could only find "Cooks" matches which are huge, and, don't quite fit on the available workspace.

If you make the first two obvious moves:-

It's clear that you need one extra match. So one match from the small square needs to be shared, and, the answer becomes simple:-

__________________
 We are alone in the universe, or, we are not. Either way it's incredible... Adapted from R. Buckminster Fuller/Arthur C. Clarke
Reply Good Answer (Score 5)
No more Good Answers. Go to first "Almost" Good Answer
abotha
Commentator

Join Date: May 2011
Posts: 67
Good Answers: 3
#2

Re: Fire Spiral (April 2025 Challenge Question)

04/01/2025 1:19 AM

I can make 4 squares by moving 4 matches.

Repositioning the 3 matches in the second vertical from left creates two large squraes and 1 small square. Moving the 4th match to close the top small square gives you the 4th.
Reply Score 1 for Good Answer
Go to Next "Almost" Good Answer
silvCrow
Guru
Popular Science - Weaponology - New Member Hobbies - Fishing - New Member

Join Date: May 2007
Location: Aloha or
Posts: 639
Good Answers: 19
#3

Re: Fire Spiral (April 2025 Challenge Question)

04/01/2025 1:39 AM

I can make 5 squares by moving 4 matches.

I'll post a picture when I find some wood matches. they are a round here someplace

__________________
 Closed biased minds are utterly impervious to any factual evidence which contradicts their beliefs
Reply
silvCrow
Guru
Popular Science - Weaponology - New Member Hobbies - Fishing - New Member

Join Date: May 2007
Location: Aloha or
Posts: 639
Good Answers: 19
#4

Re: Fire Spiral (April 2025 Challenge Question)

04/01/2025 2:04 AM

I could not come up with the matches so I stole abotha's picture. THANKS

If you steal one more from the outer edge you can get 6 squares.

__________________
 Closed biased minds are utterly impervious to any factual evidence which contradicts their beliefs
Reply
SolarEagle
Guru

Join Date: Mar 2007
Location: by the beach in Florida
Posts: 33341
Good Answers: 1813
#5
In reply to #4

Re: Fire Spiral (April 2025 Challenge Question)

04/01/2025 8:41 AM

I went 3-D...

__________________
 All living things seek to control their own destiny....this is the purpose of life
Reply
SolarEagle
Guru

Join Date: Mar 2007
Location: by the beach in Florida
Posts: 33341
Good Answers: 1813
#6
In reply to #5

Re: Fire Spiral (April 2025 Challenge Question)

04/01/2025 9:00 AM

__________________
 All living things seek to control their own destiny....this is the purpose of life
Reply
Alex. Roman
Power-User

Join Date: Oct 2011
Posts: 136
Good Answers: 19
#7
In reply to #4

Re: Fire Spiral (April 2025 Challenge Question)

04/17/2025 1:28 AM

I think a valid solution should use all the matches to form the resulting squares. There are a lot of other solutions like yours but they also don't comply with this.
Reply
Alex. Roman
Power-User

Join Date: Oct 2011
Posts: 136
Good Answers: 19
#8

Re: Fire Spiral (April 2025 Challenge Question)

04/17/2025 2:13 AM

Four other solutions with four resulting squares. The fourth square results by the move indicated by a red line in four different final positions.
Reply Score 1 for Good Answer
No more "Almost" Good Answers.
The Wizard
Power-User

Join Date: Jul 2017
Posts: 120
Good Answers: 6
#9

Re: Fire Spiral (April 2025 Challenge Question)

05/01/2025 7:04 AM

Amazing how a few matches can occupy several people's brains and intellect for some time !!
Reply Off Topic (Score 5)
Reply to Blog Entry 9 comments
Interested in this topic? By joining CR4 you can "subscribe" to
this discussion and receive notification when new comments are added.

Comments rated to be Good Answers:

These comments received enough positive ratings to make them "good answers".

Comments rated to be "almost" Good Answers:

Check out these comments that don't yet have enough votes to be "official" good answers and, if you agree with them, rate them!
Copy to Clipboard

Users who posted comments:

abotha (1); Alex. Roman (2); Randall (1); silvCrow (2); SolarEagle (2); The Wizard (1)

Previous in Blog: A Cat Dreams of Mice (March 2025 Challenge Question)   Next in Blog: The Will of A Will (May 2025 Challenge Question)

Advertisement

Got Something to Say?
Ask a Question
Start a Discussion

Search this Section
General Discussion:
Go

Search this Blog
Challenge Questions:
Go

Recent Blog Entries

CR4 Sections
Aerospace
BioMech & BioMed
Chemical & Material Science
Civil Engineering
Communications & Electronics
Education and Engineering Careers
Electrical Engineering
General Discussion
Instrumentation
Manufacturing
Mechanical Engineering
New Technologies & Research
Software & Programming
Sustainable Engineering
Transportation

Site Directories
Forum Directory
Blog Directory
User Group Directory
RSS Feeds

CR4 Rules of Conduct
CR4 FAQ
Site Glossary

Who's Online (65 right now)
Show Members
Advertisement