# Get rich quick with time travel! [closed]

The Rewinders are back!

# Background

An almost-comprehensive description of the Rewind mechanic can be found in this question, and an extensive case study can be found in my self-answer to the same. To spare you from having to pore over my ramblings, here are the salient points:

• A tiny fraction of the population has the power to rewind time. When a "rewinder" rewinds back to a point in time, everything is reset to the way it was; but she retains her memory of the time that was rewound.

• Other rewinders can regain their memory of the rewound period, but only if they could notice a difference between the original, rewound version of events and the "new" version of events.

• To prevent things from becoming ludicrous, I've put a two-minute limit on rewinds. There is a complex "stamina" system that enforces this limit, but it mostly boils down to a simple rule: a rewinder can rewind to at most two minutes before the latest time she has reached.

• Note that there is a loophole: a rewinder who gains memories from another rewinder's rewind can still go back the full two minutes. This allows two or more rewinders to perform a "leapfrog" maneuver to move information further than two minutes into the past.

# Question

The power to rewind time has a huge potential for abuse (great power, great responsibility, &c., &c.). For this reason, the Community of rewinders has decided that they would never be accepted by society, and all rewinders must hide their power from the general public. To this end, they keep a watchful eye out for any rewinder who uses their power in a way that will cause the existence of the Community to be revealed.

Our heroine Eve, a young adult of normal means, has just discovered her rewind power. Instead of revealing this power to her friends and family, she decides to keep her power secret and use it to make some easy money—but in doing so she ends up drawing the attention of the Community. The question is, how does Eve attempt to make her fortune? Assume:

• Eve has just discovered her powers and believes herself to be the only one of her kind. She thus would not take special precautions against other rewinders.

• The Community is not concerned about rewinders whose success will be attributed to luck, skill, or other mundane means (including ordinary cheating).

• Eve will avoid tedious work if she can (so no gaming the stock market with high-frequency trading, even though it will eventually be lucrative). Note also that rewinding many times takes a mental toll beyond that of the ordinary boredom and fatigue one would experience.

• She will also avoid danger if she can (no using her rewind power to become a highly-successful bank robber). Remember that rewinding is not precognition: if you die before you can rewind, you are dead permanently.

Answers should state what about Eve's method reveals her rewinder status to the Community.

The answer that could make the most money for the least cost (balancing physical and mental effort and level of risk) will be accepted. (Of course, I'll upvote all your good suggestions.)

• This is an interesting question but I don't know that the situation is constrained to the point where there aren't tons of good answers. – James Mar 8 '16 at 15:46

The rewinder plays a quiz show on TV.

For each question, the rewinder guesses randomly, waits to be told the correct answer, and then rewinds and gives the correct answer.

That could easily be dismissed as her knowing a lot of trivia, except for oddities in how she acted during the game:

• For every question, she gave the answer instantly and without hesitation.
• For one of the answers, she appeared surprised that it was correct (because she had managed to guess the correct answer on her first attempt, and thus didn't rewind.)
• In the final question, she guessed right away but then suddenly flew into a fit of rage and yelled at the host for taking too long to reveal the correct answer.

I'm not sure that going a quiz show gives the best reward for the rewinder's time, but I suspect its a way of making lots of money that the rouge rewinder would be familiar with.

• Nice, I hadn't considered game shows before... I like the public nature of this solution. – 2012rcampion Jul 12 '15 at 4:27
• So I think I'll end up using a variant of this: a well-known skeptic challenges the public to provide evidence of paranormal abilities, with a monetary prize for successful demonstration of said ability. Of course, the Community works their way onto the panel of judges so that any rewinders (including our heroine) can be 'discredited.' Like yours, this has the possibility for name recognition, but I can rewrite the paranormal contest to be non-public if it causes me problems later. – 2012rcampion Jul 30 '15 at 3:08
• @2012rcampion, is the heroine attempting to demonstrate her time-travel abilities, or is she using them to appear psychic for the prize? – Winston Ewert Jul 30 '15 at 14:01
• Either works, but probably the latter. – 2012rcampion Jul 30 '15 at 14:53
• @2012rcampion, a couple of random thoughts, feel free to ignore: at first glance, it seems a little odd to pretend to hide being a rewinder by pretending to be psychic. To hide having one unusual power by pretending to have another unusual power would seem to defeat the purpose to me. I'd also be concerned that the rewinders limits would put seemingly arbitrary restrictions on the psychic abilities which might seem to undermine the psychic claims. But perhaps thats the technique the other rewinders use to discredit her. – Winston Ewert Jul 30 '15 at 15:02

Put it all on double zero.

In the game of roulette, bets can be made while the ball is in motion. If the rewinder makes her bet on the specific number she just saw the ball land on, she can rewind six seconds and place all her money on that number. By placing the bet while the ball is moving, she is not going to change anything about its ultimate position.

Bets on a single number in roulette pay 35 to 1. Starting with \$1 and placing five correct successive all-in bets, she stands to make over 52.5 million dollars. It's difficult to reasonably attributed this success to luck or skill. Choosing the correct number five times in a row is a 1 in 79,235,168 chance (for American tables). Even someone betting over 1.5 million dollars on a single spin would gather significant critical attention. But millionaires are last century. If she bets it all one more time she stands to net over 1.8 billion dollars. While the odds of winning that many times are one in over three trillion. No one will believe she fairly won that. • Yeah but then security takes you out back, beats the crap out of you, and takes your money. – Jim2B Jul 11 '15 at 1:49 • @chaslyfromUK I don't believe that "they beat the crap out of you" if you have a big win. Is there any reason for believing that besides hollywood movies? I couldn't find a single case of such a thing happening in the real world. – Samuel Jul 11 '15 at 20:30 • @Sam Casinos don't act like the mob, but as profit-focused businesses they take cheating very seriously. If they routinely eject people suspected to be counting cards (a legitimate strategy) I think they might ask you to leave after your third or fourth win with this method (and you would probably never be allowed into a casino again). – 2012rcampion Jul 12 '15 at 2:40 • You would probably be able to keep the money, and it might make big enough news to get you noticed, but the subjective risk is pretty high (even if the actual risk is relatively low). I probably wouldn't try it... but this is the best answer so far, and with a bit of story magic It'll work. – 2012rcampion Jul 12 '15 at 3:54 • The mechanism of making money is right, the implementation is wrong. First, don't bet it all on one number. Spread it out, just win more than you're losing. Second, don't do it all at once. Cash out when you're at say 4x your stake, then go to another casino. You also aren't going to be able to make the huge sums tossed around here--casinos always have table limits. – Loren Pechtel Jul 12 '15 at 19:47 Become a stage magician. Rather than a quiz show or casino, have people pay to watch you guess things correctly. Putting on an act is "work", ongoing rathwr than a big score. So it might not pass the laziness test unless it's great fun to do. Rather than hiding and worry about being caught, you could crave attention and become famous. Rather than being worried about your secret being discovered, you would tell everyone you had special powers and everyone thinks it's an act. The preliminary to-be-rewinded action does not have to be the same thing as the comitted action. So if you are going to grab the bag that does not contain the knife, you can break character and tear off the bags, without explaination, then rewind. • This is actually exactly what Cage's character in Next (one of my inspirations for the rewind power) does. I might use this one if not for the fear of looking derivative (and the fact that, not only is it job-like, but you have to build up some reputation first). – 2012rcampion Jul 13 '15 at 4:08 • Yes, and he (normally) has a hard time limit in Next. I recall towards the end he searched everywhere at once (from an outsider's point of view) using his power. However, that movie was not criticality well-received. You might want to look at the story they got the idea from: The Golden Man by Philip K. Dick. – JDługosz Jul 13 '15 at 8:58 • So I just had some time to read The Golden Man (great read BTW) and I think I actually want to go in the entirely opposite direction. Cris can see the outcome before he makes decisions (if you even consider him to be capable of choice... maybe, like Dr. Manhattan says, "everything is preordained... even my responses"). However, I designed the rewind power so that rewinders could only react after they see the outcome of their actions. This makes observing all possible timelines impossible, and even searching a small subset is taxing and possibly dangerous. – 2012rcampion Jul 24 '15 at 1:43 Watch the powerball numbers, rewind and go buy a lotto ticket right before the numbers are announced. 320 million i think was the biggest jackpot for a$2 purchase, definitely going to be the least effort to max payoff.

Bitcoin mining/hacking.

EDIT: As far as the inadvertent aspect... lets say your character hacks the system and manages to steal the bitcion keys and then attempts to use them. Once she does this triggers some sort of alert as to their compromise. Perhaps the FBI was tracking this persons account for potential terrorism etc... And now they have a known IP of someone who has just stolen all this money. Or your heroine could have also taken the actual hard drive with the currency on it and the true owner quickly discovers this since its an absorbent amount of wealth and begins to track down the heroine.

Options trading in earnings season for stocks would require very little effort for massive leverage, (though the initial capital may be a problem here).

Casinos, watch a game of craps until snake eyes comes up 30 to 1 odds, do this a few times. Rewind and place a huge bet.

Computer hack bank accounts and wire funds into a master account. Might be too much effort.

The key here is it takes money to make money, if the person already is wealthy multimillionaire or billionaire, then if they bank another 100 million its unlikely to draw attention. Whereas if some poor street urchin suddenly has hundred million things are likely to draw attention.

The interesting thing here would be what they person would do with it as you mentioned.

• Powerball: cutoff is one hour before the drawing. Craps has the same problem as roulette, it'll just look like ordinary cheating. Jim2B already covered stocks in some detail. Cybercrime is illegal (read: dangerous) and doesn't even use rewinding. Your penultimate point is interesting: I'll add to my question that our heroine is of normal means. And as for your last point, my story never gets there, since our heroine is quickly found out. – 2012rcampion Aug 10 '15 at 21:14
• However, I love the cryptocurrency angle: although you don't explain the method, I think I know what you mean. If you can detail a method that inadvertently compromises the anonymity of the crypocurrency for the attacker, I might just have to switch my accept! – 2012rcampion Aug 10 '15 at 21:16
• Sure. Here is the article i read about a month ago which led me to think of this. arstechnica.com/security/2015/07/… – Dynas Aug 11 '15 at 12:52
• Ok, it looks like we were thinking about completely different things. You're talking about using ordinary spyware to steal unsecured bitcoin wallets (cybercrime == very illegal == too dangerous). I was talking about hijacking the blockchain itself by stealing someone's proof-of-work from the future and using it to mine bitcoins at a tremendous rate. Of course, now that I've started thinking about it, this approach won't work since the miner's transaction is included in the hash, making another miner's proof-of-work useless to Eve. – 2012rcampion Aug 11 '15 at 15:09
• Note two things: 1) Eve is not a 1337 h4x0r: although computer-savvy, she couldn't launch a botnet if you paid her to do it. Learning to pwn systems would probably qualify as too much work/effort in this case. 2) Remember that I don't want Eve to be imprisoned by law enforcement! The point is to make it obvious that rewinding is involved (to a knowledgeable observer), giving the Community a reason to contact Eve. – 2012rcampion Aug 11 '15 at 15:17

How about betting on the ponies?

In 1973, Secretariat won the Kentucky Derby with a time of 1:59.40. One minute and 59.4 seconds. So if you could get your bet in within that 6/10ths of a second time frame, and bet it all, you'd be golden. (Edit: the Preakness appears to be a little shorter, so may be a better race for this)

Alternatively, you wait until a horse with very long odds actually wins, and go back and bet it all on that horse.

• The problem with races and lotteries is that you usually can't place bets for some time before the race/drawing begins. (I had thought of this one already.) – 2012rcampion Jul 12 '15 at 4:23
• Including at a casino? – GrandmasterB Jul 12 '15 at 4:24

There is a way to cheat the system in the game Grand Theft Auto: San Andreas. You save the game, go to the betting parlor, and bet everything you have on the long shot. If you lose the bet, reload and try again until you win. Repeat.

This would work well for a rewinder. Just go to a casino or betting parlor and bet on the long shot until you win, then bet your winnings on the long shot, and repeat until you are a billionaire.

• Assuming that the odds are fair (a bet with probability $p$ of paying out will pay out $1/p$ times your bet) then you win $(1/p)^w$, where your number of wins $w$ is distributed as $w\sim\mathcal B(n,p)$. Your expected payout is $(2-p)^n$, implying that you should aim for $p$ as small as possible (long odds); however, this is a form of the St. Petersburg paradox. To maximize your minimum expected winnings (say, at a $p<0.05$ level with $n\approx 100$) it turns out you should aim for close to even odds. – 2012rcampion Aug 10 '15 at 3:24
• Otherwise this is pretty much the same as the roulette answer: from the outside it looks like my character is just cheating, and not prescient or otherwise supernatural. – 2012rcampion Aug 10 '15 at 3:25
• You cannot go back in time and place your winnings on the same bet, repeatedly. The winnings from the earlier bet will not be there after you go back in time. – fishinear Aug 6 '18 at 15:05

If you are not afraid of looking too obvious, do the following:

• Find a friend who has a stock brokerage trading account and can buy and sell options on margin.
• Look through the history of the market (or individual stock) for a particularly large jump in a market or individual stock price
(crashes are usually more spectacular).
• Convince your friend to purchase a huge number of options. Specifically, buy "naked puts" (which grants the right to sell stock at a specified price but is NOT backed by any stock - this is a very VERY risky move and I do not recommend this as any sort of ordinary investment advice).
• Set the strike price slightly under the current market value (out of the money options are cheaper).
• Doing this on margin means "you and your friend" don't have to outlay much cash to do the trade but can control many times the number of stock that out right purchasing of the stock could control.
• When the stock tanks, buy the stock at the now reduced price and call your put, allowing you to sell them at your put strike price.

But the question remains, how do you convince even a close friend to perform this very risky transaction?

It probably requires you to rewind to the months before the crash and establish a working relationship with them. Have them go through the process multiple times with small amounts of cash so they learn to trust you and "your instincts".

Then when the big crash is coming, they're more likely to risk it all on a throw of the dice.

Update 8/10/2015:
I misunderstood the question when I first wrote this. I thought you were saying that your time travelers could rewind any number of times.

Many online accounts do not give live stock prices and instead delay the prices by 15 minutes or more - unless you pay a premium price.

To use this method within the bounds of your setting, you'd need your time travelers to actually be able to execute the trade on very short notice. They might have to write a trading program or set some online account to trade stock in very short order based upon some batch program with a few keystrokes.

Since you'd only be able to utilize a few minutes of drop, it is improbable that your time travelers could make tons of money in any one trade. They'd have to use this method many times to make a starting stake of money.

Or they might just trade for a few weeks out of every year to replenish the money they spent over the previous year.

In any case, they'd need to include some option trades that turned out badly or mediocre or eventually someone would notice and ask uncomfortable questions.

• Remember a rewinder can only rewind two minutes by herself. This rules out pretty much all stock-related shenanigans except for HFT. Also she'd probably just get called out for insider trading at worst, or good luck at best; it's not apparent to an outsider that time travel is involved. – 2012rcampion Jul 11 '15 at 1:34
• Ah, I thought you might be able to go back multiple times to get further back in time. That also rules out my other answer I was about to write... – Jim2B Jul 11 '15 at 1:41
• Even if you could, I doubt you'd want to relive the same month(s) over again... it would get pretty boring =) – 2012rcampion Jul 11 '15 at 1:47
• Actually the whole process in my answer above works - provided you are already on the trade floor and ready to make that put order during a stock price drop. You can increase your chances of being there when a price drops if you are there when companies announce their earnings. If one disappoints, it's time to buy up those puts. – Jim2B Jul 11 '15 at 1:48
• I still say any reasonable person would chalk it up to insider trading, not time travel... you'd be drawing attention from the real cops, not the timecops. – 2012rcampion Jul 11 '15 at 1:50