Corn is wind pollinated and when you only have a few plants and not many, many rows it the wind is not always cooperative in dispersing the pollen over all of the adjacent flowers.
Therefore, if you plant them on mounds, the corn plants surround one another and they are all on somewhat of a slope and the pollen is more easily distributed to each plant.
It can simple fall down to the adjacent flowers and when the wind comes up, the plants are already surrounding one another and the pollen, lands on the flowers. Cool huh? It's amazing what our relatives can teach us.
I'm planting my Pink Pomegranate Popping Corn at my place tonight. Just have them soaking in some water now.