Topologically protected interface mode between two topologically distinct lattices, and waveguide path manipulation via dial-in actions. (a) A linear topological defect is highlighted by the blue background at the interface of the P-Y (I) and the Y-P (II) configurations. Dynamic properties are evaluated by taking a supercell enclosed by the dashed box. (b) Band structure for the supercell. The dashed red and blue curves represent the localized modes in the supercell. (c)–(e) A wide range of waveguide paths at the intersection of I and II can be achieved simply by dial-in actions in the lattice. Below are the numerical simulations to confirm the robust energy transport along these interfaces. Colors denote the rotation of the bottom disks.