A problem with three reel machines is that the number of combinations is only cubic – the original slot machine with three physical reels and 10 symbols on each reel had only 103 = 1,000 possible combinations. This limited the manufacturer's ability to offer large jackpots since even the rarest event had a likelihood of 0.1%. The maximum theoretical payout, assuming 100% return to player would be 1000 times the bet, but that would leave no room for other pays, making the machine very high risk, and also quite boring.