In the west, 7 is considered a very magical number.

Tarot cards have a six-pointed star system of three times seven, and 777 also represents good luck, while China also said that people have seven souls and seven spirits.

The cycle of the musical scale is 1-7,

Rainbow has seven colors,

God created the world in seven days (the last rest day).

There are seven deadly sins in the Bible.

In purgatory, seven sins flourish because of the wrong lover: pride, jealousy, anger, greed, gluttony and lust.

There are also seven candlesticks in the sky, representing seven churches, seven lights representing the spirits of seven gods and seven blessings.

Contrary to the sin in 7: wisdom, understanding, strategy, ability, knowledge, piety and fear of God.

Europeans have thought that the number seven is mysterious since ancient times, which should have been put forward by the ancient Greeks.

The Greeks believe that nature is composed of four elements: water, fire and earth, while the basic composition of society is family, which is composed of three elements: father, mother and child. Therefore, the world composed of nature and society has seven basic elements.

For another example, the ancient Greeks believed that the basic figures of the world were squares, triangles and the most perfect circles (Pythagoras school held a similar view. The sum of the angles of these figures is also seven degrees.