All phenomena are made from the four elements and thus are related in the sense of sharing the same essential nature (e.g., the four elements). Moreover, all phenomena can be classified in terms of the triad of outer, inner, and alternative things.
This principle common to most Tantric systems and is a particular feature of the Kalachakra system [meaning ‘wheel of time’ or even “time machine”]. The latter expounds on this triad under the rubrics of the outer, inner, and alternative Kalachakra. In its exposition of the three, the outer Kalachakra involves a presentation of the globe and cosmos; the inner Kalachakra involves a presentation of the adamantine (vajra) body, and the alternative Kalachakra involves a presentation of thusness (or the nature of reality). The Kalachakra system explains the mode in which each of the outer, inner, and alternative Kalachakras are made from the essential nature of the four elements. To give an easy to understand explanation of the way everything the triad of the inner, outer, and alternative is related in the sense of being one essence, one can map this principle out onto the monogram of the Kalachakra, known as the Tenfold Powerful One.