[Balin] ...with this one easy trick!

[Balin]

A multimillion-dollar building was saved by 10 cents. How?

[Doriana]

10 cents = an investment of 10 cents? a coin worth ten cents? if so, a US dime? several coins, worth 10 cents together?

Was the building saved from destruction? demolition?

[Balin]

10 cents = an investment of 10 cents? a coin worth ten cents? This if so, a US dime? several coins, worth 10 cents together? One coin, I don't know the exact currency (puzzle is BOATS) but exact currency is irrel.

Was the building saved from destruction? This demolition?

[irishelk]

Did someone intend to save the building? With the coin? Did anyone know the building was in danger of destruction? Did people expect it to be destroyed? Want it to be destroyed?

Was the coin placed somewhere that physically caused or prevented something happening? Was it relevantly paid to someone?

WAG: Is the building pictured on the coin?

[Balin]

Did someone intend to save the building? Yes With the coin? Yes Did anyone know the building was in danger of destruction? Yes Did people expect it to be destroyed? No Want it to be destroyed? No

Was the coin placed somewhere that physically caused or prevented something happening? No Was it relevantly paid to someone? No

WAG: Is the building pictured on the coin? No

[Doriana]

Would the building have been destroyed by a natural disaster? If so, flood? earthquake? lightning strike? avalanche? landslide? fire? If not a natural disaster, by a human's actions? If so, intentionally? accidentally? Electricity relevant at all? Animals relevant?

Relevant what type of building it is? Relevant how high it is? What it's made of?

Was the coin in the building when it saved it? near the building? somewhere else?

[raevenclaw]

could the building have been saved by any 10-cent coin? a specific one? could it have been saved with other coins of different values? with any coin? with some coins but not all?

[Balin]

Would the building have been destroyed by a natural disaster? Natural yes, disaster svv If so, flood? earthquake? lightning strike? avalanche? landslide? fire? None of these
If not a natural disaster, by a human's actions? If so, intentionally? accidentally? Electricity relevant at all? Animals relevant? No to all these

Relevant what type of building it is? See next Relevant how high it is? Yes What it's made of? No

Was the coin in the building when it saved it? near the building? somewhere else? This, FA

could the building have been saved by any 10-cent coin? Yes a specific one? could it have been saved with other coins of different values? Yes with any coin? Yes with some coins but not all?

[raevenclaw]

had the coin not been used, would the building have been destroyed immediately? within hours? days? weeks? months? years? relevant?
did it have to be a coin, or would any small round piece of metal work?

[irishelk]

Is there one specific coin that could be said to have saved it? Is it more like the existence of this currency generally?

Would it have been destroyed by wind? Rain? Slow decay/neglect? Was it built improperly in any way?

The party that intended to save the building: were they collecting donations? Or financing the saving of the building in any way? Did they use the coin to make a point or example? Were they appealing to the public? To another party?

[Balin]

had the coin not been used, would the building have been destroyed immediately? within hours? days? weeks? months? years? Could have been any time relevant? It is relevant that the exact time of destruction would not have been known
did it have to be a coin, or would any small round piece of metal work? Had to be a coin

Is there one specific coin that could be said to have saved it? Yes Is it more like the existence of this currency generally? No

Would it have been destroyed by wind? This Rain? Slow decay/neglect?
Was it built improperly in any way? No

The party that intended to save the building: were they collecting donations? Or financing the saving of the building in any way? Neither
Did they use the coin to make a point or example? Were they appealing to the public? To another party? No to these

[Doriana]

Was the coin somehow used in research / an experiment? And the findings showed that the building was susceptible to wind damage?

You said it was relevant how high the building is. Is it a skyscraper? If not, is it a one-storey building? two to five floors high? six to ten floors? more than ten floors?
Any other architectural features of the building relevant? Function of the building relevant? If so, residential? commercial? educational? religious? government?

[Balin]

Was the coin somehow used in research / an experiment? No And the findings showed that the building was susceptible to wind damage? but Yes

You said it was relevant how high the building is. Is it a skyscraper? Yes If not, is it a one-storey building? two to five floors high? six to ten floors? more than ten floors?
Any other architectural features of the building relevant? None that would give more light. The important feature of the building is that it's skinny, hence it's susceptible to wind damage (which you know)
Function of the building relevant? No If so, residential? commercial? educational? religious? government?

[raevenclaw]

did the coin have to be a 10-cent coin? could it have been any other kind of coin? some kinds of coin but not all? is the fact that it’s a round piece of metal relevant? or would a 10-cent bill have worked as well?
was the coin used to demonstrate something?

[trebor]

Was the coin used to pay for something? To activate something? Was it inserted into a coin slot?

Is a model of the building relevant?

[Balin]

did the coin have to be a 10-cent coin? No could it have been any other kind of coin? Yes some kinds of coin but not all? No, any coin would work is the fact that it’s a round piece of metal relevant? No or would a 10-cent bill have worked as well? No
was the coin used to demonstrate something? No

Was the coin used to pay for something? To activate something? Was it inserted into a coin slot? None of these

Is a model of the building relevant? No

[LemonCurry]

Was it a famous building?

Was the coin relevantly moved? dropped? found in an unexpected place? did it move by itself?

[Balin]

Was it a famous building? Assume No

Was the coin relevantly moved? Yes, somehow dropped? No found in an unexpected place? No did it move by itself? No

[wunderland]

Was the coin moved into the building? out of the building? moved from one place outside the building to another? dropped from the top of the building to the ground?
Did the building become less susceptible to damage from the same amount of wind? Or was the wind itself reduced somehow?
Laws against destroying money relevant?

[Balin]

Was the coin moved into the building? out of the building? moved from one place outside the building to another? Noish to this, No to rest dropped from the top of the building to the ground?
Did the building become less susceptible to damage from the same amount of wind? This Or was the wind itself reduced somehow?
Laws against destroying money relevant? No

[wunderland]

Was the coin flipped/tossed? Did someone decide to reinforce the building based on the outcome?

Failing that, was the coin rotated in place? Moved and moved back to its original position?

[Balin]

Was the coin flipped/tossed? Yes Did someone decide to reinforce the building based on the outcome? Not as in "I'll reinforce the building or not," but the outcome did decide something about it

Failing that, was the coin rotated in place? Moved and moved back to its original position? Neither

[wunderland]

When the coin was flipped, was the building already fully built? being built? being planned?
Was the decision: to do something or not? or to do something or do something else?

[Balin]

When the coin was flipped, was the building already fully built? being built? being planned? This
Was the decision: to do something or not? This or to do something or do something else?

[Balin]

HINTS:
-The coin was flipped multiple times.
-The coin flip decided the same thing every time.

[wunderland]

Was the coin used to decide how many times to do something? (e.g. will we do this? heads -> yes -> will we do it again? flip coin again -> keep going until tails)
Or was it used to make the same decision in multiple instances? (e.g. will we reinforce this wall? flip coin -> will we reinforce that other wall? flip coin -> repeat for every wall regardless of previous outcomes)

Neither of these seems like a smart way to make decisions about a multimillion-dollar construction project...

Or was it used to get something done once? (e.g. engineer thinks something needs to be reinforced, says "heads we reinforce it" and once that's agreed, flips the coin over and over until it comes up heads)

Would it help to find out exactly how many times the coin was flipped?

[Balin]

Was the coin used to decide how many times to do something? (e.g. will we do this? heads -> yes -> will we do it again? flip coin again -> keep going until tails) No, see below

Or was it used to make the same decision in multiple instances? (e.g. will we reinforce this wall? flip coin -> will we reinforce that other wall? flip coin -> repeat for every wall regardless of previous outcomes) Something exactly like this, only not for wall reinforcement

Neither of these seems like a smart way to make decisions about a multimillion-dollar construction project... Actually, it was a smart way to make the decision...

Or was it used to get something done once? (e.g. engineer thinks something needs to be reinforced, says "heads we reinforce it" and once that's agreed, flips the coin over and over until it comes up heads) No, see above

Would it help to find out exactly how many times the coin was flipped? It might. I don't know the exact number; assume around 32, just as a guess, give or take.

[wunderland]

Was the coin flipped once per floor?
Did the randomness help avoid too much regularity that might have permitted resonant vibrations?

[Balin]

Was the coin flipped once per floor? No
Did the randomness help avoid too much regularity Yes!
that might have permitted resonant vibrations? No

You now have all the pieces, I think. Care to put them in place?

[wunderland]

I'd love to, but I'm definitely still missing something... if the answer is now clear to anyone else, feel free to jump in!

[Balin]

The last piece - a piece learned a number of comments back - is what damage the building was vulnerable to.

[wunderland]

Ok so my understanding so far: some design decision had to be made in multiple instances; a coin was flipped to introduce randomness into the decisions and reduce unwanted regularity, and this made the building less susceptible to wind damage.
Hmm maybe "resonant vibrations" was the wrong term... how about "natural frequencies"? The irregularity helped prevent the building from wobbling in the wind because different parts of it would tend to wobble at different frequencies?
Do we need to find out what the decision was? Did it involve reinforcing parts of the building? Adding some external structures to break up the wind? Leaving some gaps for it to flow through?

[Balin]

Ok so my understanding so far: some design decision had to be made in multiple instances; a coin was flipped to introduce randomness into the decisions and reduce unwanted regularity, and this made the building less susceptible to wind damage. Correct
Hmm maybe "resonant vibrations" was the wrong term... how about "natural frequencies"? The irregularity helped prevent the building from wobbling in the wind because different parts of it would tend to wobble at different frequencies? That's about it, Yes. (Though "resonant vibrations" was the right term after all - I wasn't thinking of it in terms of the wind. My bad.)
Do we need to find out what the decision was? Did it involve reinforcing parts of the building? Adding some external structures to break up the wind? This Leaving some gaps for it to flow through?

****SPOILER****

During the construction of a tall, thin tower, engineers discovered that the building was susceptible to wind damage; if the wind matched the building's resonant frequency, the building could be blown apart. So they attached external baffles to the outside of the building to break up the wind, but the baffles needed to be put on randomly so as to break up the wind enough. To decide which sections of the building would have baffles or not, they flipped a coin.

(This also comes from Matt Parker's Humble Pi, which WiZ mentioned in one of his puzzles. I wondered if he'd spotted this story as well.)

Nicely done.

[wunderland]

Cool, nice puzzle and that sounds like an interesting book...