In this instance it was to illustrate a joke, but the triangle and circle together can mean various things. The triangle either within or interlocking with a circle symbol is a common image in alchemy and many religions. The symbol has numerous meanings including spiritual sight, higher knowledge, the unity of the trinity of God, the divine union of the body, mind and spirit, masculine and feminine, or universe, the symbol for protection and power, and the totality of wisdom.
fasab 
What does this mean?
In this instance it was to illustrate a joke, but the triangle and circle together can mean various things. The triangle either within or interlocking with a circle symbol is a common image in alchemy and many religions. The symbol has numerous meanings including spiritual sight, higher knowledge, the unity of the trinity of God, the divine union of the body, mind and spirit, masculine and feminine, or universe, the symbol for protection and power, and the totality of wisdom.