Cryptopot.com is legit and it's base on a "Math Ponzi Model", but this model by it self has nothing wrong. But when people use it to mislead investors or promise any guaranteed payout, that's when people start to judge like a "bad ponzi". If there's nothing to hide, no hidden fees and if every detail of the game is made public it can't be called has a scam because all information is public.
Then it's up to the player to decide if they want to gamble and play. We like transparency and the CryptoPot team are trustworthy and time will prove that.
So yes, it's possible to have a legit ponzi, the providers just need to be a honest person and treat their players with respect.