Einstein said that there is no mathematical trick that can help you win at roulette. But others believe that it is possible to manipulate the way the roulette wheel and bookies are set up to give themselves an advantage. The idea is that you can bet on the structure in such a way that you are guaranteed to win.
There is no such think as a 100% roulette strategy. It's only an illusion. People think because they can cover 80 - 90% of the board and show small profit compared to amount they wager that they figured out a system. But guess what even know your odds are greater to win at beginning of every spin.