Dispersions around the Dirac points in sonic crystals give rise to various extraordinary transport proper-ties of sound waves. In particular, with tilted Dirac cones, the acoustic Dirac crystals will exhibit obvious anisotropic properties. When the Dirac cone is titled to a certain degree, a unique type-III Dirac point emerges with the extreme anisotropic-wave-transport property, which features the crossing of flat bands and linear dispersions. Recently, some quantum and artificial structures have been proposed to realize dif-ferent types of Dirac points, where the type-III Dirac point in soni...
