Here the player starts by staking one unit per bet, if the player wins they continue to bet one unit. The progression begins when a player loses the one unit bet.
This system involves a progression where you bet the sum of the last two bets you have made - 1,1,2,3,5,8,13,21,34,etc... The Fibonacci should be used infrequently and with small stakes for fun. It is definitely a win sometimes, lose sometimes system. You can see for yourself, the system makes you bet quite large sums after a few losses in a row. Be warned this system is not for the faint hearted and if you are wise you'll limit the use of the Fibonacci system.