Above are some Yantras and Symbols in India. Some of them are spiritual and some others are used by "Tantriks" for helping them to get out of stress and tensions. There are thousands of them in temples.
Gurdjieff explained that the Enneagram symbol has three parts that represent three Divine laws, which govern all of existence. The first of these is the "circle", a universal mandala, used in almost every culture. The circle refers to unity, wholeness and oneness, and symbolizes the idea that the God is one.
Within the circle we find the next symbol, the "triangle". Traditionally, in religions, this refers to the trinity of:
The Law of Seven. (Hexad) –Seven sins and virtues of which, as King Solomon states that the Lord specifically regards "six things the Lord hate, and the seventh that are an abomination unto Him". The Catholic Church also recognizes the seven sins viz; Envy, Gluttony, Greed, Lust, Pride, Sloth, Wrath; and seven virtues viz; Kindness, Temperance, Charity(Generosity), Chastity, Humility, Diligence, Patience.
The Vedas and the Gita have given the guidelines of negative traits that we should avoid. They are the so-called 6 sins: Kama – lust; Krodha – anger; Loba – greed: Moha – attachment: Mada – pride; Matsarya – envy/ jealousy.