The Maha Yantra above Symbolise Blessings Of Maa DhumaVati. 

The diagram composes of  triangle with a dot (bindu) in the center, which sits inside a six sided star, bordered by a circle and sits on top of a lotus flower which has eight petals all of which are inside a
square structure.

Maha Yantra is a diagram which is meditated upon. Meditate on the yantra. 

~ AdiGururJoy