Merkabas are tetrahedrons, made by the intersection of two, three-sided pyramids. Merkabas are great tools for working on your spiritual transformation, which some believe is the whole purpose of our existence.
Merkabas are believed to form a spiritual shield around the holder. In upper dimensions, the geometric shape of the human energy field is said to be in the shape of a Merkaba. Thus, meditating with a Merkaba helps us to connect with our higher self.