From: [email protected] [mailto:[email protected]]

right. i understood that. but this is where i see the

contradiction: from

the viewpoint of theobservera clock which remains

static for 20 minutes

cannot also simoutaneously vary a mere 5 minutes from reality.

I suppose my perception is that it’s OK because:

a) It’s not ‘static’, given the implied variable ambiguity implied by

the ‘~’. (Maybe each call to the clock should use sequential characters

from ‘|/-’ instead of ‘~’ to show it spinning and changing.

b) The observer is relying on the clock to know how much time has

passed. With access to no other timepieces, the observer has no idea

that it has stayed static for 20 minutes, just that it has stayed static

for…what feels like a long time.

yes, i see that. still, it seems flawed. think about it on

a number line,

which does not wrap as times do.

[snip]

I think I see what you’re saying here. It feels to me like you’re saying

that because the short term variation cannot be truly brownian (being

both clamped and having a unidirectional filter on it), that the overall

statistical variation is flawed. I’m not enough of a statistician to

know if this is the case or not, but it feels true: given a random

chance of overshooting or undershooting, the time will probably

overshoot on the average since it has less chances to come back towards

the middle.

Ensuring an even distribution of over/undershoot is desirable, and

probably achievable with differently weighted probabilities for

over/undershooting. That seemed enough like hard work to me to put that

as the fifth Extra Credit item in the original.

great quiz btw!

I hope so. It seems like such a simple problem (and I don’t think

because it’s under- or ill-specified), but I’ve yet to have the “Ah-HA!”

moment in the shower that gives me an elegant way to accomplish it. I’m

looking forward to trying to solve it this weekend, and very much

looking forward to see what other people come up with.