I've been getting loads of copies of the roulette spam - you know? The one that appears to be a misdirected email going:
please tell me when you will send me your roulette trick? You promised you'll send it few weeks ago :(
yo mate, ok I'll give you my trick but if you give it someone else I'll kill you :) you know in roulette you can bet on blacks or reds. If you bet $1 on black and it goes black you win $1 but if it goes red you loose your $1. but I found a way you can win everytime: ...
It's one of those mathematical illusions: really hard to find any fault in it, so... is it a quick route to easy money?
Kochanski wrote a good explanation of how the language tricks you as well as the maths, so read that. Executive summary of the maths: "Basically, this algorithm is a way of generating lots of small wins and a few huge losses."
Someone else even wrote some software to prove it - they ran the software lots of times and found exactly that effect, that they ended up with loads of small wins and a few huge losses, meaning that on average you're out of pocket.
Apparently there's even a name for this kind of faulty-logic: a martingale.