What does it mean to wrap 7 grains of rice in red cloth?

Put seven grains of rice under the pillow to ward off evil spirits. In addition, when going to a funeral, you can put a few grains of rice in your pocket or wallet to ward off evil spirits.

It is said that playing mahjong with seven grains of rice in his pocket can make Ma You's thinking and patience active and lasting, change Ma You's fortune at the same time, even improve his mentality, and finally achieve the goal of winning money.