
Show HN: Stellar Jackpot - thijser
http://www.stellarjackpot.com
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floatrock
Neat. You're trusting a website that doesn't list who runs it (whois says it's
a guy named Mathijs Vogelzang out of Paris) or what their intentions are to
provide a fair lottery to anonymous addresses. Given enough lotteries you
could backtrace the results and make sure the distributions are
probabilistically random, but what's stopping the owner from entering a
sufficiently large pool and 'randomly' selecting an address he controls as the
winner?

Oh, and for providing this service you automatically lose 2% off the top.

There are far better ways to waste your virtual disney dollars.

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knd775
I'm pretty sure the poster (thijser) is Mathijs Vogelzang based on his
username. His HN profile is a few years old and he says where he works on his
profile. I'm not saying whether people should trust this or not, but I think
you may be being a bit unfair.

~~~
codingdave
I don't this he is being the slightest bit unfair. At least in the US,
lotteries make a lot of money for the people running them, but that is
normally shared with local communities or governments. If you participate in
lotteries, you pretty much are guaranteed to be throwing your money away, but
at least losing people do get some benefits from the system, as the proceeds
get spent in their area.

In this case, one guy just collects the money. No matter what his intentions
or honesty, he collects.

If people want to throw him their "cash", fine... but they should absolutely
realize what they are doing.

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thijser
I'm the creator, thanks for the insights. This was really just a fun project
to explore the Stellar API (which is really good, and I hope they will reach
their goal and transform international payments).

It seems the attention on hacker news drew quite some payments into the
system, whereas I had thought that it would just stay in the play money range
forever. The lottery aspect I hadn't thought about. I'm eager to transform the
model to make it less lottery like as I certainly don't want to violate any
laws, but am a bit unsure about exactly how. There could be a small chance
that 100% of the money goes to a charity, or that there is somehow a matter of
skill involved in the exact amount you send. (FYI, the only other piece of
information that can be sent along with a Stellar payment is one 32-bit
integer ID). Any suggestions are welcome.

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dreamdu5t
Don't listen to people trying to pressure you on how you spend you money.
People love to shame others.

You made a lottery. Nobody has to play. Do whatever you want with the money.
Don't give it to charity because someone else told you to.

~~~
noso
I agree with this post, you created it and people are using it so do what you
want with it. It is a great idea, So well done!

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gojomo
"…redistribution game…" – what a lovely euphemism!

And finally, a website to directly address the problem that anonymous lottery
operators have too little wealth, and credulous altcoin lottery players have
too much.

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mful
I can't decide if this is fun, but fiscally pointless, or kinda brilliant.

It looks like a pretty simple app, which I doubt took too much time to put
together, and is likely incredibly cheap to run. Assuming the most recent two
hours are more representative of engagement than the previous two (not a given
by any means, and no I haven't been tracking this before then), it looks like
it's producing several hundred Stellars an hour minimum for the creators.

Stellars aren't worth much right now, and may never be (I'll leave that sort
of speculation to those with more knowledge of the subject), but this seems
like a cheap and quick way to build a stockpile.

Anyway, food for thought.

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knes
I just won the last jackpot of 37682.96 stellar. Not sure what I can do with
it hehe.

~~~
fela
play again :P

or give it to a charity, I think there are a few that have a stellar account,
for example miri

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chrisfosterelli
I wonder if you could game that jackpot. Statistically, with even-odd tickets
the net value of the ticket is always less than the ticket cost -- meaning
statistically you loose money (ex: a $2 ticket, on average, has a return of
$1.50). If you could monitor the jackpot and, at the very last minute, more
than double the current pot then you'd have over a 50% chance of winning.
You'd win some and loose some, but statistically over time I think you'd end
up positive.

Any mathematicians want to chime in?

EDIT: As fela, zck, and thedufer pointed out below, this would not work in
fact. Thank you guys for the math lesson!

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thedufer
If you exactly double the pot right before a drawing, you'll have a 50% of
losing 50% of the pot (what you put in) and a 50% chance of winning 48% of the
pot, with an expected value of, you guessed it, losing 2% of your money each
time.

It's not a coincidence that this 2% is equal to the cut taken. That will
always be your expected loss. Unless it does not behave as advertised, you
can't game it.

~~~
chrisfosterelli
I said "more than double the pot". So your odds would be over 50%. And you win
the _entire_ pot if you win, unless I'm misunderstanding? You don't have a 50%
chance of winning 48%, you have a >50% chance of winning 98%.

~~~
zck
The site says "The draw is weighted by payment amount". I'm assuming that's
linear -- if I put in 1 stellar, and you put in 2, you're twice as likely to
win than you are. If the weighting is different (say, you're four times as
likely to win), then that changes the math.

Let's say that before you put anything in, the pot holds X stellar. You then
put in Y stellar. So I'm assuming that you win with Y/(X+Y) probability. If
you win, you win .98(X+Y). If you lose, you lose everything.

So your expected value is the chance you win (Y/(X+Y)) times the return
(.98(X+Y)).

    
    
         Y      
        ---  * .98 * (X+Y)
        X+Y
    

The (X+Y) parts cancel, and you end up with .98Y, or less than what you put
in. And since we didn't use the fact that Y>X, it's independent from the
actual values of X and Y, so it holds no matter what they are^1.

[1] Assuming they're positive, and X+Y is nonzero.

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Egidius
Is there any way I can get str's by buying them somehow? It seems like I'm a
bit too late with registrating my Stellar account

~~~
gst
[https://justcoin.com/](https://justcoin.com/) would be an option (appears to
currently have the largest Stellar volume out of the few exchanges that trade
it). Here are the current prices:
[http://coinmarketcap.com/currencies/stellar/](http://coinmarketcap.com/currencies/stellar/)

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hrjet
Just for fun, what would be the optimal strategy to play this game?

If you have x amount to spare, you could either put all x in one round, or
spend x/N in N rounds.

I guess, the probability of winning might be optimal for some N > 1, but I am
not able to come up with a formula for it.

Further optimisation of the N>1 strategy could be to stop entering into a
round after winning and making a profit.

~~~
fela
The expected amount is always 98% percent of what you put in, so the optimal
strategy is to not play at all :)

It depends what you are optimizing for. In most cases playing multiple times
will make you win very slightly less in the median case, countered by the fact
that you can win multiple jackpots (obviously not too likely an event)

And stopping strategies usually mean having a big probability of winning
little but have a small chance of losing a lot. Basically a reverse lottery,
but you still lose on average.

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joshdance
Take 2%. That is almost a standard credit card fee. We are trying to get away
from those level of fees with new types of currency.

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desireco42
Apparently I won. :) So I know it pays back.

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knes
Awesome idea., I just sent some Stellar to it.

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jdietrich
I take it you have a lottery license?

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davidjgraph
I take it he lives in a country where one is required?

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Kiro
I don't know of any modern country where it's not required.

