The influencing factors of coal arch camber in planomural coal bin and coal drop pipe with rectangular or circular cross section during coal drop are studied theoretically.
Noteheads may be black (a circular or oval shape filled in) or white and are used on the staff to indicate pitch. The shape of noteheads has differed historically, as in plainchant.
The metaphor representing the Yin and Yang or the first male and female connection - the right and left eyes of Horus is the Vesica Pisces becoming the symbol for the First Light.