« first day (2929 days earlier)      last day (40 days later) » 

2:37 AM
Q: How to solve a 4x4 pyraminx?

WsssPlease include parity I have tried many methods but it does not work Please help

3:02 AM
Q: Tiling twelve 5 x 10 rectangles with ten sets of the twelve pentominoes

Bernardo Recamán SantosI have ten copies of each of the twelve pentominoes. Can I use all of them to completely tile twelve 5 x 10 rectangles?

2 hours later…
5:31 AM
Q: Sum of digits of numbers

I'm NobodyLet S be a function such that S(N) is the sum of digits of N. N belongs to natural numbers, and N < 10²³. Find the number of N that satisfies the equation: S(N) = S(S(N))

9 hours later…
2:10 PM
Q: Disguising a Rubix Cube Rotation

MCKhib_MealI'm wondering if there's a way to disguise the total rotation of a cube. For example, if I wanted to rotate the (solved) cube I could obviously just apply a 90 degree yaw rotation,however, I would like it so that the rubiks cube gets scrambled and unscrambled in the process. For example take the ...

2:35 PM
Q: Patrick and Rachel go to a tennis tournament with other 7 couples

Mattia VanzettoPatrick and Rachel go to a tennis tournament with 7 other couples. Each round is a single's match (1 vs 1). Nobody plays against his partner and nobody plays twice with the same player. At the end of the tournament Patrick asked everyone how many people they played against, and found that each on...

1 hour later…
3:49 PM
Q: A barrel contains 10l of whiskey, another one contains 10l of coca-cola. If I do the following operation

Mattia VanzettoA barrel contains 10l of whiskey, another one contains 10l of coca-cola. If I do the following operation in two steps: 1 step) with a glass I transfer 200ml of whiskey from the first barrel to the second one, and I mix the barrel very well. 2 step) After that, with a glass I transfer 200ml of the...

4:14 PM
Q: You have my sword – A signed letter from Gladys

Jafe Letters from Gladys are geography-themed standalone crosswords. Each puzzle has five thematic answers, which are places, sights or landmarks in or around a certain location (in this case, an autonomous community). Each thematic answer is notable enough to have its own article in the English Wiki...

1 hour later…
5:28 PM
Q: You go to Starbucks with some colleagues, everybody takes a cappuccino. Every cappuccino contains

Mattia VanzettoYou go to Starbucks with some colleagues, everybody takes a cappuccino. Every cappuccino contains only coffee and milk (at least some coffee and some milk) and no other ingredients, but everyone in a different ratio. If in your cappuccino there is 50% of the total milk used to make your and your ...

2 hours later…
7:36 PM
@Sphinx Argh. Had all but two clues on this for over an hour now! You've stumped me this time @Jafe - 2D and 14D just won't click for me (though I'm sure of the answer for 2D, just not the wordplay...).
Ah, just got 2D - one to go!
Huzzah, cracked it! (Apologies for the thinking out loud - needed a sounding board!)
8:22 PM
hehe nice job
Another good one @Jafe - you've got cryptics down to an art now...
9:10 PM
Q: WIll Romeo meet Juliet?

Mattia VanzettoRomeo and Juliet try to meet each other everyday at a certain place between 12:00 and 13:00. They arrive at the place at a random time between 12:00 and 13:00 and they wait 15 minutes (but never after 13:00), if nobody shows up they come back home. Everyday, which is the probability that they mee...

9:23 PM
Q: Is my question off topic?

I'm NobodySum of digits of numbers I recently posted this puzzle, I'm not sure why it is not well received. How can I make sure that this does not happen next time?

9:35 PM
Worlds collide... Tonight, in conversation with my wife about a book she used to read as a child, I found after going down a Wikipedia rabbithole that the book's female author had written under a pseudonym, and that strangely she had chosen another female name ('strangely' since a lot of female authors of the time would write under male names to better their chances of getting published...). So I googled why she did that...
...top result was a question on Literature.SE...
...asking exactly the same question less than 2 months ago...
...AND IT WAS ASKED BY @Rand'alThor !
Q: Why did Sarah Chauncey Woolsey adopt the pseudonym Susan Coolidge?

Rand al'ThorToday I learned that Susan Coolidge, author of What Katy Did and other novels, wasn't the real name of the author, Sarah Chauncey Woolsey. However, I couldn't find any clear information on why she adopted this pseudonym. It's not a male pseudonym, as in the case of many other female 19th-century ...

One day I will wake up and find that my life is all a Matrix-esque illusion created by Stack Exchange.
10:25 PM
Q: Colour in a 5 by 5 grid, with evolution rules, so that the starting grid is the same as the output grid

R1s1ble I don't know the answer to this question, but after having spent some time trying to solve, I suspect it is impossible. (Hopefully I didn't miss something really obvious...) I'm hoping someone can supply a proof!

11:09 PM
11:27 PM
I know I spoke about this with some of you in the run-up to Christmas, but it's taken all the time since then to prep it - my 100th puzzle is finally live! Here's hoping all the bugs have been caught at long last... It's a biggun...
(Do point out any errors, by the way - I'd prefer to fix them than let them slide... Unless they break the whole thing and make me cry in a corner, of course...)
Q: I got ninety-nine problems - so here's another one!

StivTo date, on Puzzling.SE I have contributed (counting: 10, 20, 30...) 99 problems to the site. So to mark my 100th, here's a massive meta-puzzle to celebrate the occasion! Task Solve the nine sub-puzzles and meta-puzzle featured in the image below to find the final 9-letter answer. Partial answe...

Q: We are part of the equation too

Leonard Eulerhttps://i.stack.imgur.com/KTRkF.jpg What does this weird equation relate to in the picture. How can we make sense of the equation and rights now

11:55 PM
congrats on #100! that one looks like it's taken a ton of effort to make
reminds me a little of the $100 question (which also would have made an appropriate 100th, i suppose)

« first day (2929 days earlier)      last day (40 days later) »