A big hello to all the new people who have been kind enough to follow me on Twitter – almost up to 14,000 now!

Here is this week’s puzzle …

Can you create 8 equilateral triangles with just 6 matches?

Update: You are not allowed to break the matches! Also, what is the greatest number of equilateral triangles you can make with the matches?

As ever, please do not post your answer, but do say if you think you have solved it and how long it took. Have a great weekend and i will see you next week.

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Yes, few minutes.

It’s the one where we think in more than 2D:) But I only got 6 so far

Hmm, about a minute to solve it…

Here’s a different one – 4 equilateral triangles with 6 matches without crossing them.

No problem:), but this one is 3D.

This one I can do, took a few seconds. thinking tails not heads 😉

but can’t see the answer to the main one yet. 😦

I hate these puzzles, because the rules aren’t clear (although I’m pretty sure that I have the ‘correct’ answer). Equilateral triangles live in the world of geometry, matches don’t. Can we break the matches, superimpose them, cut them up into Cantorian dust? I’m thinking that the ‘correct’ answer has twice as many triangles as the answer that doesn’t contain as many physical objections (if that’s not giving away too much)…

There’s no restriction on breaking them, so in theory you can make any amount of shapes

Excatly. You could break them each into 5 pieces and end up with 27 equilateral triangles, or split them each into 14 pieces to get 118. But I don’t think this is the solution he’s looking for.

2 minutes with pen & paper. 2D, no breaking.

but do the matches lie flat? ie are they true equilateral triangles?

How does “not lying flat” mean “not equilateral?” An equilateral triangle simply is a triangle with all three sides the same length, regardless of dimensionality.

about 3 mins? only with pen and paper, and I only got it so quickly because of cultural learning.

I got a solution in just seconds. Oy vey! Perhaps all these puzzles are sharpening my problem-solving skills. (Or maybe I just got lucky.)

I think some people are overthinking this. My solution is 2D and involves no breaking. (Though I’m curious to see how Simon solved it.)

oi vey

But can you make just 4?

Yay I did one. Couple of minutes

about 10 seconds

Done it in a few seconds. Now trying to solve the “4 equilateral triangles with 6 matches without crossing them.” puzzle

done the second puzzle to0.

Nice one. Got it quickly as did my 10 year old daughter.

But could any friends called David get it?

Plato helped me with the 6 matches 4 triangles.

Instantly

Can I use a lighter instead?

Looks like this one was very easy… maybe any of you want to try this: http://games.lumosity.com/chimp.html ?

Please!!!!!

Easy one. More lunar buses, please!

Easy as heck. The time it took to read the question.

So please very much try this: http://games.lumosity.com/chimp.html !

I think I got it right in a about one minute with the help of pen and paper as well.

No.

Wow finally a Friday Puzzle I managed to do! (Saying that I have probably got it wrong now!)

Few seconds and 2 drawings away… yes, easily solvable.

I’m intrigued by what you asks… “how long we took?”… the idea is to gauge population’s subjective time? How many dead ends in average we experience before the final solution? Or it would be interesting to count the time we took effectively? But then, no one would be able to connect the times to correct answers (someone who’s said has found it, maybe has not). Lateral thinking like’s Simon is also interesting (actually, my first reaction before pick a paper was to break the matches) because some puzzle are solvable by bending the rules we thought there was there… the question is when to bend them or not.

i can make 10 🙂

which includes 8

took me a minute or 5 though

let me change that into 13…

but that still includes 8

Less than 10 seconds. Easy peasy!

About 5 seconds for the first question. Still thnking about the second…

There are some star problem solvers here

Gevalt! This one seems to easy…I think I got it in a few seconds (first thing that popped in my head)….

But not re beating the chimp… why noone wants to give it a trial? It requires miliseconds! And is really difficult even if you don’t have to think too much.

Took me a few minutes ’cause I had to find some matches…. no pen or paper….. just matches….lol…..giggle…..

Five seconds for the first question. Don’t want to think about the possibilites that arise if I’m allowed to break the matches…

< a minute with paper and pencil… Me likey

I didn’t break any matches and it took about a minute. The solution makes me feel quite festive!

Took me forever, until I realized I had already drawn the answer. Duh!

‘Update: You are now allowed to break the matches! ‘ – I assume that should be NOT, rather than NOW?!

There are much more difficult matchstick puzzles than this one.

Almost instantaneous. But I have no idea about the max # of equilaterals, i.e. wether there is a possibilty of >8.

About a minute with pen and paper to solve the first question, without breaking any match but getting 2 big triangles of the same size plus 6 smaller ones with the same size. Don’t know yet the answer to the 2nd question.

Found in 9 seconds a solution with 9 triangles out of 6 matches.

Yes.

About 40 seconds.

took a minute or so for 8

Just a couple seconds for 8. I think my answer to the second one is also “8.”

One minute.

About 10 seconds.

I’ve enjoyed your posts and have embedded one of your videos (Top 10 quirky science tricks) in my blog 🙂

Regards!

El Gonzi

Wow, for the second question. Now, that’s a nice twist considering how many triangles people are saying they achieve. I’m really interested to see the solutions they came through because I think I can prove that 8 is the maximum number of triangles we can achieve in the plane (It’s not that complicated to reach there and from it, the number 8 as the cube of 2, will came naturally). So, what I overlooked?

A different question is how many ways of building those 8 triangles there are. Obviously, if we deem different two ways where the triangles are of different size, then the number of those ways are infinite. But if we cater for a different criteria, for example, how the triangle’s apexes might be oriented, then the number might be finite. To proceed further, that criteria would have to be established.

I thought I found a 6 triangle solution, but actually there were 8. 😀

just about one minute

yes, a minute or so.

Got it in about 30, seconds… 2D, very simple

rather under half a minute. I had paper-and-pencil ready as usual for the Friday Puzzle, then once I had read the puzzle I thought it would be better to go to the kitchen and get a matchbox. I had then solved the puzzle before even rising from my chair – it was the thought of the matchbox that did it!

Took me just long enough to draw 6 lines to move my solution from visualizing it to verifying it.

not “equilateral” but i did it, not too long, though i guess you could say i “cheated”

well, now i have it without cheating….

when i read the text, exactly 5s

Just a few minutes but I had to draw it out first.

3 seconds! easy.

Believe it or not, this was curiously easy…. 16 seconds, and that’s total time of getting pen and paper and drawing it out… now for more configurations…

try 12 sticks to make 8 triangles