This is not a click-bait article, we are giving you the answer right away. Slot machines aren't designed to cheat players.
Cheating at slot machines might be interesting to some, but the general idea behind slot machines is for players to have fun and try out their luck, not only earn money.
There are some slot machine hacks that worked on old-school slots. One of the most popular ways to manipulate a slot machine was to use a coin to trick the registered balance.