Who is Martingale?

Martingale is a betting system where on every loss, you double your bet, and on every win, you reset your bet back down to your lowest bet. You are guaranteed to profit one unit on every win, but it is much more likely that you will lose too many bets in a row to continue playing.

More information on Wikipedia: https://en.wikipedia.org/wiki/Martingale_(betting_system)