“…However, this leaves the door open for an altogether different type of spinors having both scalar and pseudo-scalar bi-linear quantities vanishing identically, called singular [1,2]. Singular spinor fields, or flag-dipole spinor fields, may be unusual but they still have many important things to tell [3][4][5][6][7][8][9][10]. In fact, these spinors can be further split into subclasses, obtained when the axial-vector bi-linear quantity, that is the spin, is zero, and in this case they are called flagpole spinors, or when the antisymmetric tensor bi-linear quantity, that is the momentum, is zero, and in this case they are called dipole spinors.…”