What are the invincible formations in Plants vs Zombies Endless Edition?

Placement of sunflowers: This refers to the placement of formed sunflowers. The attack in the water is relatively small, so it is safer to put two sunflowers in the water. Sometimes zombies will drill out of the water, usually under the sixth lotus leaf, so the first five positions are safe. In addition to the four cannons, another position is to put sunflowers. But we should also consider that bungee zombies are caught from the air, so they are placed in the last three columns, so that they can be protected by plant umbrellas. Because cannons don't have to worry about bungee zombies. Generally speaking, as long as there are three sunflowers after everything is built, four sunflowers can be guaranteed in the early stage. It is most appropriate to put two sunflowers accumulated on more than 6000 land near the waterway in the fourth column at a faster speed, because these positions sometimes happen to be the landing points of small zombies thrown by giant zombies. If you put a cannon, it will sometimes be eaten by small zombies, which will cause great losses. So it is safe to push the cannon forward, so it is more appropriate to put a sunflower in this position.