Hacking into Paris’ Cheats on Streets

preet
3 min readJan 14, 2017

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“Guess and win €100!!”, an elderly Asian woman interrupted me as I was walking from the Eiffel Tower to the metro line on a windy Paris evening. Being extra cautious since I was traveling alone, I kept walking and dodged a group of 6 people staring at some setting of cups and a ball on the ground.

As I walked further, I encountered a group of about the same size every twenty meters or so. Something really compelled me to observe what is going on.

After looking at the game for a minute or so, I could figure out the rules.

The one who is hosting the game jumbles the three cups with the ball under one of them. Typically two people place bets of €50 each. The person who calls first, that is, makes a guess from three cups gets €150. If that person is wrong, the other participant has to chose from the other two cups and if they get it right, they get €100. If both of them fail, the host gets to keep €100.

I quickly did a sanity check of feasibility of hosting such a game by calculating the expected money earned by the host which turned out to be positive.

[expected money earned by the host = -1*P(first person winning)*50-P(first person losing and second person winning)*0+P(both first and second participants losing)*100 = -(1/3)*50-(2/3)*(1/2)*0+(2/3)(1/2)*100 = +50/3]

The whole system appeared fairly simple until I realized that the group I was observing had this fool who was constantly loosing. “Must be a rich careless folk, clearly doesn’t know how to dress accordingly though”, I thought to myself and moved on to the next group doing a similar exercise.

Here, I again encountered a lady who didn’t look very affluent and did a superficial job showing her discontent while constantly losing money. I sensed something fishy.

It then occurred to me that both the gentleman in the previous group and the lady here who were losing every time called their cup before the other person who was participating.

Though this didn’t make sense. First person losing all the time with money in the system meant that on an avg the host wasn’t making any money since the second guy who played had a 50% chance of making money which meant avg 0 for the host. Perhaps they were waiting for someone outside the system who would place the first bet.

I verified this hypothesis by observing about 10 games in which every time the person who called first lost! Since most travelers would play a maximum of 3–4 times, it hardly got any attention. Further, there were 2 people in each group who used to switch turns in calling first and losing.

Another interesting insight that I got was that in each group, there were one or two people who used to pull tourists to participate.

They would use silly hacks like telling people to translate for them in simple English, what the host of the game was saying and try to attract them to the bait.

Suddenly, I realized that I had been observing this circus for nearly half an hour and Paris had more beautiful sights to offer.

On my way back though, I happened to meet an Indian settled there who somehow noticed me taking keen interest in the game from a distance. He warned me not to engage in anything of this sort since even if you win, these thugs give you fake currency.

That just made perfect sense!

The person who loses first puts fake money into the system and they lose nothing at all. It’s a win situation for the host anyway!

I was blown!

Paris never ceased to astonish me, be it it’s beautiful architecture, awesome food or the wonderful people. This was just another side of the coin I guess!

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preet
preet

Written by preet

I am fascinated by how fitness, knowledge & focus have positive nth order effects. Endorphins monkey. EU/ US tech investing at EQT Ventures.

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