Does the Martingale system work on roulette or blackjack?

No. Doubling after each loss does not change the edge on any single bet, and every round carries a negative expectation; a sequence of negative-expectation bets sums to a negative expectation whatever the staking pattern. Two hard walls finish the argument. Table limits: starting at EUR 1, eight consecutive losses cost EUR 255 and the ninth bet must be EUR 256, which a EUR 200 table maximum simply refuses. Finite bankrolls: that ninth bet risks EUR 256 to net EUR 1 overall. The system converts many small wins into one rare, very large loss. No staking plan beats a negative edge.