Best...Puzzle...Ever....

[Nightfall]

My favorite deadly door trap:

There is a large steel door with four buttons. Each button has a letter, A,C,D and E.

Besides the wall is an inscription:

To open door, the first and last are needed. Sing and know well these songs and your path will be clear.

Sing a song of sixpence, pocket full of rye
London Bridge is falling down
Mary had a little Lamb
Little Jack Horner sat in a corner.

Can you guess how this works?

 

[Nightfall]

....

 

[Sagiro]

Here's a very tough one:

1000 prisoners are arranged in a big circle and chained to numbered posts from 1 to 1000 such that prisoner #1 is next to prisoner #1000. Their evil captor decides he will execute 999 of them. He begins by killing #1, then skips a prisoner and kills #3, then skips a prisoner and kills #5 and so on. When he's come full circle he continues by always skipping one surviving prisoner and killing the next one. In other words, corpses are removed and no longer count. Surviving prisoners are not moved: they remain chained to the post they started with. What will be the number of the one who survives in the end out of the 1000?

If anyone can solve this without using a computer or a physical model, I'll be very impressed.

I don't know if I'm right, but here's my guess after not thinking about it enough.

Spoiler

After zero trips around the circle, the survivors are #1, #2, #3, #4 #5, etc.
After one trip around the circle, the survivors are #2, #4, #6, #8, #10, etc.
After two trips around the circle, the survivors are #4, #8, #12, #16, #20, etc.
...

So, after n trips around the circle, the survivors are #2^n, and every multiple of that number (up to 1000, that is). Following that pattern, one would deduce that, eventually, the only numbers left would be 256, 512 and 768. Since 768 would been the last survivor of these, 256 would get knocked off, 512 would be spared, and then 768 would be killed. So my guess is that #512 is the last man standing.

 

[der_kluge]

Some of these are good.

But, you guys need to post some solutions, lest I go insane trying to figure these out!!

 

[kipling]

I pinned all my hopes on the wording, as follows:

In other words, corpses are removed and no longer count.

In which case, the survivor is # 1, by definition.

However, he is fastened to pole 512. (Same reasoning as used elsewhere.)

Which reminds me of the 1000 doors opened and closed puzzle, which is quite similar, but involves opening closed doors as well.

 

[BryonD]

I GIVE UP! Where'd you find this?

Spoiler

The middle guy on the right knows he is wearing black.

If he were wearing white, the guy behind him would see two whites and immediately know HE was wearing black and so he would easily yell out the answer. He lack of response indicates that he is seeing one black and one white. Thus, the second guy MUST be wearing black.

 

[Nightfall]

Some of these are good.

But, you guys need to post some solutions, lest I go insane trying to figure these out!!

Give you a hint. Bardic Song ability...and Scales...

 

[Joshua Randall]

The vastly underrated Book of Challenges has some excellent D&D puzzles / room traps.

The problem with pure brain-teaser traps is that in D&D, players can often bypass them using spells or abilities. "Screw weighing these 12 balls - we'll just cast commune to find out the answer." or "The heck with this so-called unopenable door. I'll cast etherealness and go through the walls."

 

[Crothian]

I like puzzles, but they aren't for the characters they are for the players. Do people find it's hard to do puzzles while trying to stay in character and what that character would possibly be able to solve?

 

[rigur]

How about this one:

Four people are set for execution. They are buried in sand with only their heads above ground. They can't turn their head. Then there's a wall placed between the first and second person (as shown on the pic). Then someone places a hat on their head. They all know there are 2 white and 2 black hats. They will be killed in 60 seconds, unless one of them says outloud what color his own hat is. He cannot say anything else. They can't communicate between each other. They can't see the hat on their own head.

After a little while, one of them knows for sure what color his own hat is.

Took me 15 minutes to figure this one out...

Second guy from the right will know which color (black)he has based on the fact that the guy behind him doesen't shout out that he has a black hat and that the guy in front of him is wearing a white hat.