The elements are incorrectly known as earth, air, fire and water, which is using Physical-universe labels for things which are Magick-universe in nature.
The original items are nothingness with the power to manifest anything (that item is the lower one), the upper one being Everything-already-created. The item in front of the body is really caused-creation (i.e. creation which flows) and the item behind the back is uncaused-creation (i.e. creation which just appears, without any link to any cause). These last two are usually the other way around for female bodies.
This system provides energy for the body to use, and with practice can be used to provide energy to be projected outside the body (as in the flows of Chi projected by an experienced T’ai Chi practitioner), with the center of the system acting as a Source/Ground for energy flows, and which operates using specific spinning Magick-Universe-Matrix Triads.
The Elements have multiple line-sources/grounds going outwards from each of the 4 parts.